Understanding the Working Time of Developers in IT Companies in China and the United States

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Understanding the Working Time of Developers in IT Companies in China and the United States
FEATURE: ONLINE DEVELOPER COMMUNITY

  Understanding the                                                                             WORKING OVERTIME IS a common
                                                                                                social problem in modern life. Ac-

  Working Time of
                                                                                                cording to the American General So-
                                                                                                cial Survey in 2018, more than 27%
                                                                                                of employees experienced mandatory

  Developers in IT                                                                              overtime work in the United States.1
                                                                                                In March 2019, a project called
                                                                                                996ICU was launched on GitHub2 to

  Companies in China                                                                            debunk the infamous work schedule
                                                                                                in some Chinese IT companies, called

  and the United States
                                                                                                996. Employees who follow the 996
                                                                                                work schedule labor from 9:00 a.m. to
                                                                                                9:00 p.m. for six days per week. The
                                                                                                exposure of the abnormal working
  Jiayun Zhang, Yang Chen, Qingyuan Gong, and Xin Wang,                                         hours on social media quickly caught
  Fudan University, China                                                                       the attention of the public and was re-
                                                                                                ported by leading news media around
  Aaron Yi Ding, Delft University of Technology, The Netherlands                                the world.3–5
                                                                                                    The heated discussions represent a
  Yu Xiao, Aalto University, Finland                                                            pressing demand to better understand
                                                                                                the work rhythm, which is tightly cou-
  Pan Hui, University of Helsinki, Finland, and Hong Kong                                       pled with people’s living conditions.
  University of Science and Technology, China                                                   Extended work hours are correlated
                                                                                                with adverse health.6 The expanded
                                                                                                schedule could cause sleep distur-
  // We identified three temporal patterns shown in                                             bances,7 predispose citizens to major
  commit activities among Chinese and American                                                  depressive episodes,8 and lead to in-
                                                                                                creased mortality.9 In the domain of
  companies and found that Chinese businesses are                                               software engineering, it is quite com-
  more likely to follow long work hours than American                                           mon for developers to switch among
  ones. We also conducted a survey on the trends of,                                            multiple activities10 and software proj-
                                                                                                ects11 over the course of a week.
  reasons for, and results of overtime work. Our study                                              It is important to analyze the dif-
  could provide references for developers to choose                                             ferent working time across compa-
                                                                                                nies. For developers, understanding
  workplaces and for companies to make regulations. //                                          the general schedule of a company
                                                                                                could help them learn about its cul-
                                                                                                ture. For managers and executives in
                                                                                                industry, knowing the general work-
                                                                                                ing time of their employees could
                                                                                                help them set expectations and labor
                                                                                                conditions to achieve greater work
                                                                                                efficiency. However, previous stud-
                                                                                                ies12,13 related to schedules in the
                                                                                                software engineering domain were
                                                                                                mainly project or individual based, so
                                                                                                were limited for interpreting working
Digital Object Identifier 10.1109/MS.2020.2988022
                                                                                                time at the organizational level. Fur-
Date of current version: 11 February 2021                                                       thermore, working time is likely to be

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Understanding the Working Time of Developers in IT Companies in China and the United States
influenced by local cultures. There is              to work during regular off hours               that can be used to understand human
a lack of investigations into the work-             than on other dates.                           behaviors.14,15 Online developer com-
ing hours of IT companies across dif-             • We conducted a survey of 92 de-                munities are a special kind of social
ferent countries.                                   velopers to understand the situa-              network that enable developers and or-
    This article aims to fill in this gap           tion of, reasons for, and results of           ganizations to conduct collaborative de-
by studying and comparing the work-                 working overtime. We found that                velopment and share code. The commit
ing time of software developers in IT               working overtime is prevalent                  logs can be retrieved from the online de-
companies from two representa-                      among developers. People tend to               veloper communities if the projects are
tive countries, i.e., China and the
United States. Our goal is to explore
both the similarities and differences
between working time in modern IT
companies through valid data inter-
                                                         GitHub is a leading online developer
pretation to reflect on general IT work                   community that has a population
conditions and their extended impact,                     of 31 million developers and hosts
such as on labor productivity and
societal pressure.                                        more than 96 million repositories.
    We crawled and used a real-world
data set of code submissions from
GitHub, a leading online developer
community. We applied a machine                      work extra hours when there are               uploaded and made public by compa-
learning model to cluster the tempo-                 deadlines or emergencies. Devel-              nies. GitHub is a leading online devel-
ral pattern of code submissions and                  opers who work less frequently                oper community that has a population
conducted a comprehensive analysis to                on weekends are more likely to                of 31 million developers and hosts more
investigate the data. Furthermore, we                believe additional working hours              than 96 million repositories.
carried out a qualitative survey-based               could increase their productivity.                Figu re 1 shows the temporal
study to better understand developers’                                                             distributions of commit activities in
working time. The major contribu-               Background and                                     three companies collected from GitHub
tions of this article are as follows.           Related Work                                       in the form of a heat map. Company A
                                                                                                   is a leading Internet company in China
 • We designed a data-driven ap-                Background                                         with a history of more than 20 years.
   proach with machine learning                 During the software development                    Company B is a start-up in China that
   techniques and identified three              process, developers use Git, a widely              was founded in 2014, maintaining a
   temporal patterns shown in the               used open source distributed version               platform for discovering and sharing
   commit activities among 86 IT                control system, to keep track of their             technologies. Company C is an Amer-
   companies on GitHub. We found                progress. New code is submitted via                ican company that offers business and
   that Chinese companies are more              Git by using “commit,” which records               employment-oriented services and op-
   likely to follow long working hours          the code submission information, in-               erates via websites and mobile apps.
   than their American counterparts.            cluding author, local time, and the code           They represent three distinct patterns:
 • We present an empirical analysis             to be added or removed. The frequency              1) developers in company A who work
   on the extent of overtime work               of commits during a period of time re-             overtime during weekdays, 2) those
   in these companies. We found                 flects, to some extent, whether devel-             in company B who work overtime on
   that in China, developers in                 opers are actively working on software             both weekdays and weekends, and
   large companies are more likely              projects during that time. The tempo-              3) those in company C who follow typi-
   to work overtime than those in               ral distribution of the commit activities          cal working hours.
   small companies. Also, if devel-             could reflect the circadian and weekly
   opers in Chinese businesses have             work pattern.12                                    Related Work
   to work during the Lunar New                     Online social networks record                  Researchers explored the factors that
   Year holiday, they are more likely           rich information about user activities             may influence employees’ working

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Understanding the Working Time of Developers in IT Companies in China and the United States
FEATURE: ONLINE DEVELOPER COMMUNITY

time. Beckers et al.16 proposed that                                 typically worked from 10:00 a.m. to                      the working time of software develop-
the likelihood of working overtime is                                6:00 p.m. and did not work at night                      ers in IT companies from two repre-
influenced by gender, age, job require-                              or on weekends very often. Eyolfson                      sentative countries, i.e., China and the
ments, and salary. In addition, situ-                                et al.13 reported that commits made be-                  United States.
ations of working overtime in some                                   tween 12:00 a.m. and 4:00 a.m. were
domains were studied. It was reported                                most likely to have bugs.                                Research Questions
that American scientists were likely to                                  Although some tangential evidence                    We aimed to study the working time
work at night, while most Chinese sci-                               has been found regarding the working                     of IT companies in China and the
entists worked on weekends.17                                        hours of individuals and certain proj-                   United States. Our study is guided by
   In the sector of software develop-                                ects in the software engineering do-                     three motives, which yield five subse-
ment, Claes et al.12 investigated the                                main, investigations into interpreting                   quent research questions. First, we de-
time stamps of commit activities of soft-                            working time at the organizational                       fined a company’s work rhythm as the
ware projects from Mozilla, Apache,                                  level and comparing the working time                     pattern of its time allocation for code
and a local Finnish IT company to                                    of IT companies in different countries                   submissions during weekdays and
study developers’ working hours. They                                are lacking. In this article, we conduct                 weekends. We identified representative
found that two-thirds of the developers                              a study to understand and compare                        work rhythms among IT companies
                                                                                                                              and examined general discrepancies
                                                                                                                              between companies of the two coun-
                                                                                                           0.0150             tries in terms of work rhythms.
                       Mon.
     Day of the Week

                                                                                                           0.0125
                       Wed.                                                                                0.01                 • Research question 1: What are
                                                                                                           0.0075
                         Fri.                                                                                                     the representative work rhythms
                                                                                                           0.005
                                                                                                           0.025                  among IT companies in China
                        Sun.
                                                                                                           0                      and the United States?
                                0      3        6        9      12    15         18      21
                                                        Hour of the Day                                                         • Research question 2: How do
     (a)                                                                                                                          the work rhythms of IT compa-
                                                                                                           0.0150
                                                                                                                                  nies vary across countries?
     Day of the Week

                       Mon.
                                                                                                           0.0125
                       Wed.                                                                                0.01                   Second, we sought a deeper un-
                                                                                                           0.0075             derstanding of overtime work in various
                         Fri.                                                                              0.005              groups of companies and during differ-
                        Sun.                                                                               0.025
                                                                                                                              ent time periods. We explored whether
                                0      3        6        9      12    15         18      21                0
                                                                                                                              there is a relationship between the in-
                                                        Hour of the Day
                                                                                                                              tensity of overtime work and company
     (b)
                                                                                                           0.0150
                                                                                                                              size. We set 10,000 employees as the
     Day of the Week

                       Mon.                                                                                                   boundary between large and small
                                                                                                           0.0125
                       Wed.                                                                                0.01               companies according to Fortune18 and
                                                                                                           0.0075             divided companies into two groups.
                         Fri.                                                                              0.005              We tested whether there is a difference in
                                                                                                           0.025
                        Sun.                                                                                                  the ratios of overtime commits between
                                0      3        6        9      12    15         18      21                0
                                                                                                                              large and small companies. In addition,
                                                        Hour of the Day
                                                                                                                              we investigated whether developers
     (c)
                                                                                                                              are more likely to make commits in regu-
                                                                                                                              lar off hours around holidays than other
FIGURE 1. The temporal distributions of commit activities in three companies: (a)                                             dates. We targeted the Lunar New
Company A, (b) Company B, and (c) Company C. The x-axis represents 24 h of the day                                            Year holiday for Chinese companies and
and the y-axis represents seven days of the week. The color bars on the right show the                                        the Christmas holiday (the week start-
mappings of commit frequency to the darkness of the color: the darker the color of a                                          ing from Christmas day) for American
time slot, the higher the commit frequency during the period.                                                                 companies.

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Understanding the Working Time of Developers in IT Companies in China and the United States
• Research question 3: Is there a              which there are 12,041,474 commits                 silhouette coefficient score indicates
   relationship between overtime                and 9,050 developers from 39 compa-                better defined clusters. When k = 3,
   work and company size?                       nies in China, as well as 232,497,720              the silhouette coefficient score is the
 • Research question 4: Is overtime             commits and 53,594 developers from                 highest. We also observed the sizes of
   work influenced by holidays?                 47 companies in the United States.                 the clusters and visualized patterns
                                                We released the full list of companies             of each k. We found that when there
   Third, to compensate for the re-             and the repositories in our data set.19            are more than three clusters, the new
sults of empirical analysis on the                 Notice that our data set only in-               ones have very few individuals and do
crawled data, we carried out a quali-           cludes public open source projects on              not show distinct patterns. We chose
tative survey-based study. We asked             GitHub, which may only reveal the                   k = 3 based on the results.
developers about the situations of              publicly visible work activities. Be-                  Figure 2(a) and (b) shows the av-
overtime work in their companies                sides, we can only analyze the com-                erage commit frequency of the de-
and the reasons for working over-               mit activities with the data set, which            tected patterns during each hour of
time. In addition, to understand the            might not reveal the exact working                 the day on weekdays and weekends.
results of overtime work, we asked              hours since there are other work-re-               The characteristics of each pattern
developers about the frequency of               lated activities such as meetings and              are summarized as follows.
working on weekends and their per-              project planning. Still, the time distri-
spectives on productivity during ex-            bution of commits could be an impor-                • Pattern 1: These companies
tra working hours.                              tant indicator for the working hours.                 endure longer working hours on
                                                                                                      weekdays than others.
 • Research question 5: What are                Representative Work Rhythms of IT                   • Pattern 2: While the developers
   the trends of, reasons for, and              Companies                                             in these companies work from
   results of working overtime?                                                                       9:00 a.m. to 6:00 p.m. on week-
                                                Research Question 1: What Are the Repre-              days, following regular work-
Empirical Analysis of                           sentative Work Rhythms of IT Companies                ing hours, they make more code
the Work Rhythms of IT                          in China and the United States?                       submissions on weekends than
Companies                                       To identify the work rhythms of                       those in other businesses.
                                                companies, we calculated the com-                   • Pattern 3: These companies follow
Data Collection                                 mit frequencies in different time pe-                 typical working hours on week-
We used the GitHub application pro-             riods and used clustering algorithms                  days, from 9:00 a.m. to 6:00 p.m.,
gramming interface to obtain the                to analyze the data. For each com-                    and developers rarely submit code
commit logs from GitHub. We only                pany, we computed the ratio of the                    changes on weekends.
collected publicly accessible informa-          commits in each hour of the day on
tion. We consulted GitHub about our             weekdays to all commits on week-                   Research Question 2: How Do the Work
study and received their approval for           days. We performed the same calcu-                 Rhythms of IT Companies Vary Across
the data collection and analysis in             lation for weekends. Following the                 Countries?
our research. The data set was col-             calculations, we obtained the 24-di-               T he nu mb er of compa n ie s f rom
lected between 1 and 27 May 2019,               mensional vectors for weekdays and                 China and the United States with
covering the accounts of 101 IT com-            weekends, respectively, with each                  each pattern is shown in Figure 2(c).
panies and their source repositories            element representing the average                   Patterns 1 and 2 are more prevalent
on GitHub. They are a combination               commit frequency in one of the 24 h.               among Chinese companies, while
of large technology companies and               We concatenated the two vectors as                 American businesses mainly fol-
start-ups in the United States and              a 48-dimensional vector and then                   low pattern 3. To statistically vali-
China. We filtered out those commit             applied k-means, a classical cluster-              date the observation, we applied the
logs without time zone information              ing algorithm, to discover the repre-              Fisher’s exact test. For each pattern
and only selected companies with at             sentative work rhythms.                             p i, we assumed the null hypothesis
least 30 contributors and 300 com-                  To select the number of clusters                H 0 is that Chinese and American
mits. Finally, we formed our data set           k, we iterated k from 2 to 8 using the k-          companies are equally likely to fol-
with a total of 86 companies, among             means clustering algorithm. A higher               low p i . Since we tested the three

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Understanding the Working Time of Developers in IT Companies in China and the United States
FEATURE: ONLINE DEVELOPER COMMUNITY

hypotheses simultaneously, we ap-                                                likely to follow p i than Chinese                        had the greatest number of commits in
plied the Bonferroni correction to                                               businesses. The results indicate                         a day. Given the time stamps of com-
limit the family-wise error rate. The                                            that businesses in the two countries                     mit activities of a company, for each
significance level was 0.0167, which                                             are significantly different in these                     starting time t, we computed the num-
is equal to 0.05 divided by the num-                                             three patterns: pattern 1: p value =                     ber of commits made between t and
ber of hypotheses. If the p value is                                              2.706 # 10 -8, OR = 23.47; pattern 2:                   t + 8 h. We selected the interval with
under 0.0167, we could conclude                                                  p value = 0.0166, OR = 5.06; pattern                     the highest number of cumulative com-
that Chinese and American com-                                                   3: p value 1.359 # 10 -12, OR = 0.02.                    mits as the working hours of the con-
panies are significantly different                                                                                                        sidered company. Since companies may
in terms of pattern p i . We also re-                                            Insights Into Working Overtime                           change their working hours over time,
ported the odds ratio (OR). The dis-                                             in IT companies                                          we restricted the time of commits from
tance from 1 of an OR indicates the                                              To investigate the situations of overtime                2018 to 2019, to reflect the recent labor
magnitude of the effect size. An OR                                              work, first we need to determine the                     status of developers in these companies.
greater than 1 indicates that Chi-                                               companies’ regular working hours. We                     Still, we removed businesses with fewer
nese companies are more likely to                                                follow Claes et al.’s method.12 Compa-                   than 30 contributors or 300 commits.
follow p i than American businesses                                              nies are assumed to follow an 8-h work                   Finally, we obtained a data set with 25
while an OR lower than 1 indicates                                               schedule on weekdays. For each com-                      companies in China and 39 companies
that American companies are more                                                 pany, we determined which 8-h slot                       in the United States.

                                                                                                                                          Research Question 3: Is There a
                           0.025                                                                                                          Relationship Between Overtime Work
      Commit Frequency

                            0.02                        Pattern 1                                                                         and Company Size?
                           0.015                        Pattern 2
                                                        Pattern 3                                                                         We set 10,000 employees as the
                            0.01
                                                                                                                                          boundary between large and small
                           0.005
                                                                                                                                          companies. For each company, we
                               0
                                                                                                                                          calculated the ratio of commits out-
                          –0.005
                                                    0            6                12                  18                    24            side working hours to commits in to-
                                                                            Hour of the Day                                               tal. Figure 3(a) shows the aggregated
      (a)
                           0.025                                                                                                          results in violin plots. To statistically
      Commit Frequency

                            0.02                        Pattern 1                                                                         validate whether large businesses
                           0.015                        Pattern 2                                                                         have significantly different amounts
                            0.01                        Pattern 3                                                                         of overtime commits than small
                           0.005                                                                                                          ones, we performed the Mann–Whit-
                               0                                                                                                          ney U test. Results are measured by
                          –0.005                                                                                                          p values. The significance level is
                                                    0            6                12                  18                    24
                                                                            Hour of the Day                                               0.05. We reported Cliff’s delta (d) for
      (b)                                                                                                                                 effect size. d ranges from -1 to 1. If
                           Number of Patterns

                                                                                                                                          d is greater (less) than 0, it quanti-
                                                1                                                                  U.S.
                                                                                                                   China
                                                                                                                                          fies how often the numbers of over-
                                                2
                                                                                                                                          time commits in large companies are
                                                                                                                                          higher (lower) than those in small
                                                3                                                                                         ones. In China, large companies have
                                                                                                                                          more overtime commits than small
                                                    0       10            20         30                    40                50           companies do (p value = 0.028,
                                                                        Number of Companies
      (c)                                                                                                                                 d = 0.53). In the United States, we
                                                                                                                                          did not detect a significant difference
FIGURE 2. The clustering results on (a) weekdays and (b) weekends show the                                                                in the number of overtime commits
average commit frequency of each detected pattern during each hour of the day on                                                          between large and small companies
weekdays and weekends. (c) The number of companies in each pattern is described.                                                          (p value 2 0.05).

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Understanding the Working Time of Developers in IT Companies in China and the United States
Since there are more employees in            hours between the week before or after                                    One possible reason is that during
large companies, they may set more              the holiday and other dates (p value 2                                 the daytime on the Lunar New Year
comprehensive regulations and stan-             0.0167). In American companies, we                                     holiday, people are likely to take part
dardized workflows than small compa-            did not detect a significant difference in                             in various activities outside the home,
nies, to better manage their employees.         the four types of time periods (p values                               such as visiting friends, so they might
The regulations for holiday arrange-            2 0.0167).                                                             have to work after they come back.
ments and benefits for the overtime
work may increase employees’ willing-
ness to work overtime. However, due
                                                       Outside Working Hours      0.7
to the standardized workflows, the pe-
                                                         Ratio of Commits

ripheral work of programming, such as                                             0.6
waiting for approval or communicat-                                               0.5
ing with colleagues in different depart-                                          0.4
ments, may take up a lot of time during                                           0.3
working hours, so developers might                                                0.2        Large
                                                                                             Small
have to work on their projects after                                              0.1
working hours.                                                                                       China                              United States
                                                                  (a)
Research Question 4: Is Overtime                                                   1
                                                       During Regular Off Hours

Influenced by Holidays?
                                                                                  0.8
                                                           Ratio of Commits

We compared the commits in regu-
lar off hours in four time periods: one                                           0.6
week before the holiday, during the                                               0.4
holiday, one week after the holiday,
and other dates. For each type of time                                            0.2
period, we only considered companies                                               0
that have at least one commit during                                                    Before Holiday       Holiday         After Holiday         Other Dates
that period. The results of Chinese                               (b)
and American companies are shown
                                                                                   1
                                                       During Regular Off Hours

in Figure 3(b) and (c). We performed
the Mann–Whitney U test to vali-
                                                           Ratio of Commits

                                                                                  0.8
date whether there was a significant                                              0.6
difference in the commits in regu-
lar off hours before, during, and after                                           0.4
the holiday and other dates in each                                               0.2
country. We applied the Bonferroni
                                                                                   0
correction and set the significance level
                                                                                        Before Holiday       Holiday         After Holiday         Other Dates
as 0.0167. We also reported Cliff’s
                                                                  (c)
delta (d), which measures how often
the number of commits in regular off
hours during a specific period of time          FIGURE 3. The degree to which work is performed outside the commonly
are higher or lower than those of other         expected working hours. The rotated kernel density plot on each side shows the data
dates. In Chinese companies, if devel-          distributions. The black bars in the middle represent the quartile range, the extended line
opers have to work during the Lunar             represents the 95% confidence interval, and the white point represents the median. (a)
New Year holiday, they are more likely          The ratio of commits outside working hours to total commits is given in large and small
to toil during regular off hours than           companies in China and the United States. The ratio of commits during regular off hours
on other days (p value = 0.0044, d =            to total commits made (b) before, during, and after the Lunar New Year holiday and other
0.53). We did not detect a significant          dates in Chinese companies and (c) before, during, and after Christmas and other dates
difference in the commits in regular off        in American companies.

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Understanding the Working Time of Developers in IT Companies in China and the United States
FEATURE: ONLINE DEVELOPER COMMUNITY

Survey Study on                                      prevalent among developers and that                      productivity, while six (40%) held the
Overtime Work                                        most do not enjoy it.                                    opposite view and two (13.33%) were
We designed a survey study to tackle re-                                                                      neutral. Among the 13 people who
search question 5: “What are the trends              Reasons for Working Overtime                             sometimes work on weekends, eight
of, reasons for, and results of work-                To understand the reasons for work-                      (61.54%) believed that extra work-
ing overtime?” We asked developers                   ing overtime, we set a multiple-choice                   ing hours increases productivity, while
about how they and their colleagues                  question and listed nine common rea-                     four (30.77%) held the opposite view
are experiencing overtime work,                      sons as options according to the pilot                   and one (7.69%) was neutral. Among
what makes them work overtime,                       test. Participants could choose one or                   the 26 people who never work on
and how they think of the productiv-                 more options and their responses are                     weekends (but work overtime on
ity during extra working hours. Our                  shown in Figure 4(b). The most com-                      weekdays), 18 (69.23%) believed extra
survey was reviewed and approved by                  mon reason for working overtime is                       working hours increases productivity,
the Research Department of Fudan                     approaching deadlines. The least three                   while eight (30.77%) did not.
University, Shanghai, China. Before re-              voted reasons indicate that providing                       Weekend recovery is helpful for
leasing the survey, we first conducted               incentives are not that effective to en-                 improving work performance on
a pilot test with seven developers from              courage developers to work overtime.                     weekdays.20 Too much work on week-
different companies to fill out the ques-                                                                     ends may cause fatigue and decrease
tionnaire, then interviewed them for                 Extent of Overtime Work on                               productivity.
comments on the survey. We modified                  Weekends and Its Relationship

                                                                                                              I
the survey according to their feedback               With Productivity
and then published it online. We first               We set a multiple-choice ques-                                n this article, we cross-checked
sent questionnaires to 10 developers                 tion about the frequency of working                           the working time of developers
from selected IT companies (including                overtime on weekends. We asked par-                           at IT companies in China and
large technology companies and start-                ticipants to choose one of the follow-                   the United States. We identified three
ups in China and the United States in                ing options: never work on weekends,                     representative work patterns in our
our data set) and then asked them to                 sometimes work on weekends, work                         data set and found significant differ-
pass along the survey link to other de-              on either Saturday or Sunday every                       ences between companies in the two
velopers. Our online version had 1,516               weekend, work on both Saturday or                        countries. The findings indicate that
views and we received 92 responses.                  Sunday every weekend, or other work                      Chinese companies are more likely to
Except for two participants who                      schedules. We set another multi-                         follow longer working hours, which
wanted to keep their company infor-                  ple-choice question about whether                        clearly acknowledge the 996 phe-
mation confidential, 52 were from                    extra working hours increase produc-                     nomenon in the Chinese IT industry.
Chinese companies and 38 were from                   tivity. Participants could choose one                    Our results show that developers in
American companies.                                  option among the following: extra                        large companies in China are more
                                                     working hours increase productivity,                     likely to work overtime than those in
Self-Reported Experience                             extra working hours do not increase                      small companies. Also, if developers
of Working Overtime                                  productivity, stay neutral, or have no                   in Chinese companies have to work
To understand developers’ experiences                experience of working overtime.                          during the Lunar New Year holi-
of working overtime, we included five                    We cross-checked the responses to                    day, they are more likely to toil dur-
statements and asked participants how                the two questions and plotted a Sankey                   ing regular off hours than on other
the statements fit with their situations             diagram, i.e., Figure 4(c), to display the               dates. According to the results of our
in the form of five-point Likert scale               responses. All four people (100%) who                    survey, working overtime is preva-
questions. For each statement, par-                  work on both Saturday and Sunday                         lent a mong developers a nd t he
ticipants could choose one of the fol-               every week replied that extra working                    mo st common reason for it is ap-
lowing five options: strongly disagree,              hours does not increase productivity.                    proaching deadlines. Developers
disagree, neutral, agree, and strongly               Among the 15 people who work on                          who work less frequently on week-
agree. We plotted a bar chart for the                either Saturday or Sunday during the                     ends are more likely to believe extra
Likert scales, as shown in Figure 4(a).              weekend, seven (46.67%) responded                        working hours could increase their
We find that working overtime is                     that extra working hours increases                       productivity.

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Understanding the Working Time of Developers in IT Companies in China and the United States
Strongly Disagree          Disagree          Neutral            Agree              Strongly Agree

                         Most of my colleagues work overtime.            45%                            13%                             42%
               My company provides benefits for overtime work.           59%                            16%                             26%
                                       I enjoy working overtime.         52%                            33%                             15%
                                           I work during holidays.       60%                            20%                             21%
                              I work more before/after holidays.         65%                            20%                             15%
                                                                 100           75    50        25       0     25             50       75      100
           (a)                                                                                      Responses

                                                        Deadline                                                                      33.3%
                                                      Emergency                                                                       32.3%

                                    Need Extra Time for Coding                                                                        24.7%

                                          Company Requirements                                                                        19.4%
                                                   Peer Pressure                                                                      16.1%
                                                 Enjoying Coding                                                                      15.1%
                                                                                                                                       7.5%
                                    Good Working Environment
                                           Travel Reimbursement                                                                        6.5%

                                                           Bonus                                                                       1.1%

                                                                     0               10                20                    30               40
                                                                                                    Responses
                                    (b)

                                                                               Have No Experience Working Overtime: 25 (27.2%)

            Never Work on Weekends: 51 (55.4%)

                                                                         Extra Working Hours Increases Productivity: 38 (41.3%)

            Sometimes Work on Weekends: 13 (14.1%)

            Other Work Schedule: 9 (9.8%)

                                                                                              Extra Working Hours Do Not Increase
            Work on Every Weekend, Either Sat. or Sun.: 15 (16.3%)                                         Productivity: 26 (28.3%)

            Work on Every Weekend, Both Sat. and Sun.: 4 (4.3%)                                              Remain Neutral: 3 (3.3%)
         (c)

FIGURE 4. The results of the qualitative survey. (a) The developers’ self-reported experience of working overtime. The numbers on the
right are the percentages of respondents who agree or strongly agree with the statements. The numbers on the left are the percentages
of respondents who disagree or strongly disagree with the statements. The numbers in the middle are the percentages of respondents
who stay neutral. (b) The numbers on the right are the percentages of respondents who choose the reasons for working overtime. (c) The
frequency of working overtime on weekends and perspective on whether extra working hours increases productivity. The number and
percentage of respondents who agree with each statement are displayed next to the label.

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Understanding the Working Time of Developers in IT Companies in China and the United States
FEATURE: ONLINE DEVELOPER COMMUNITY
ABOUT THE AUTHORS

                                             JIAYUN ZHANG is an undergraduate                                              QINGYUAN GONG is a Ph.D. candidate in
                                             student in the Shanghai Key Laboratory of                                     computer science at Shanghai Key Labora-
                                             Intelligent Information Processing, School                                    tory of Intelligent Information Processing,
                                             of Computer Science, Fudan University,                                        School of Computer Science, Fudan Univer-
                                             Shanghai, 200433, China. Her research                                         sity, Shanghai, 200433, China. Her research
                                             interests include machine learning, data                                      interests include network security, user
                                             mining, and user behavior analysis and                                        behavior analysis, and computational social
                                             modeling. Further information about her                                       systems. Gong received a B.S. in computer
                                             can be found at https://jiayunz.github.io.                                    science from Shandong Normal University,
                                             Contact her at jiayunzhang15@fudan                                            Jinan City, China. She has published papers
                                             .edu.cn.                                                                      in IEEE Communications Magazine, ACM
                                                                                                                           Transactions on the Web, World Wide Web,
                                                                                                                           ACM International Conference on Informa-
                                                                                                                           tion and Knowledge Management, and
                                                                                                                           International Conference on Parallel Pro-
                                                                                                                           cessing. Further information about her can
                                                                                                                           be found at https://gongqingyuan.word
                                                                                                                           press.com/. Contact her at gongqingyuan@
                                                                                                                           fudan.edu.cn.

                                             YANG CHEN is an associate professor with                                      XIN WANG is a professor at Shanghai
                                             the Shanghai Key Laboratory of Intelligent                                    Key Laboratory of Intelligent Information
                                             Information Processing, School of Computer                                    Processing, School of Computer Science,
                                             Science, Fudan University, Shanghai, 200433,                                  Fudan University, Shanghai, 200433, Chi-
                                             China, where he leads the mobile systems                                      na. His research interests include quality of
                                             and networking group. His research interests                                  network service, next-generation network
                                             include online social networks, Internet archi-                               architecture, mobile Internet, and network
                                             tecture, and mobile computing. Chen received                                  coding. Wang received a Ph.D. in computer
                                             a Ph.D. from the Department of Electronic                                     science from Shizuoka University, Japan.
                                             Engineering, Tsinghua University, Beijing,                                    He is a Member of IEEE. Further informa-
                                             China, in 2009. He serves as an associate                                     tion about him can be found at http://
                                             editor in chief of Journal of Social Comput-                                  homepage.fudan.edu.cn/xinw2013/home/.
                                             ing. He is a Senior Member of IEEE. Further                                   Contact him at xinw@fudan.edu.cn.
                                             information about him can be found at https://
                                             chenyang03.wordpress.com/. Contact him at
                                             chenyang@fudan.edu.cn.

   We provide suggestions for both                                 tion of China under grants 62072115,                       2. GitHub, “996.ICU.” [Online]. Available:
developers and managers. For devel-                                71731004, 61602122, and 61971145;                             https://github.com/996icu/996.ICU
opers, we suggest that they should be                              CERNET Innovation Project under                            3. People’s Daily, “Compulsory over-
aware of the difference in work time                               grant NGII20190105; the Research                              time work should not become a com-
culture among different companies                                  Grants Council of Hong Kong under                             pany culture.” [Online]. Available:
when choosing workplaces. For man-                                 grant 16214817; the 5GEAR project;                            http://bit.ly/2krzJPw
agers and executives, we suggest that if                           and the FIT project from the Academy                       4. S. Wang and D. Shane, “Jack Ma en-
their employees are experiencing over-                             of Finland. Yang Chen is the corre-                           dorses China’s controversial 12 hours
time work, they should ensure that they                            sponding author of this article.                              a day, 6 days a week work culture,”
have adequate rests on weekends.                                                                                                 CNN Business. [Online]. Available:
                                                                   References                                                    https://cnn.it/2lURsiC
Acknowledgments                                                     1. GSS Data Explorer, “Mandatory to                       5. BBC News, “Jack Ma defends the ‘bless-
This work was sponsored by the                                         work extra hours.” [Online]. Avail-                       ing’ of a 12-hour working day.” [On-
National Natural Science Founda-                                       able: http://bit.ly/2lWqcjT                               line]. Available: https://bbc.in/2m1f3hq

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Understanding the Working Time of Developers in IT Companies in China and the United States
ABOUT THE AUTHORS

                              AARON YI DING is a tenure-track assistant                            PAN HUI is the Nokia chair of data science and
                              professor in the Department of Engineer-                             a full professor of computer science at the Uni-
                              ing Systems and Services, TU Delft, Delft,                           versity of Helsinki, Helsinki, 00014, Finland. He
                              2628CN, The Netherlands, and an adjunct                              is also a faculty member in the Department of
                              professor (Dosentti) in computer science at the                      Computer Science and Engineering at the Hong
                              University of Helsinki, Helsinki, 00014, Finland.                    Kong University of Science and Technology,
                              His research interests include edge computing,                       Hong Kong, and an adjunct professor of social
                              Internet of Things, and mobile networking                            computing and networking at Aalto University,
                              services. Ding received a Ph.D. with distinction                     Espoo, 02150, Finland. Hui received a Ph.D.
                              from the Department of Computer Science,                             from the Computer Laboratory, University of
                              the University of Helsinki. He is a two-time                         Cambridge, U.K. He has published more than
                              recipient of Nokia Foundation scholarships                           200 research papers with over 12,500 citations
                              and received the best paper award at ACM                             and has approximately 30 granted/filed Euro-
                              EdgeSys 2019 and ACM Special Interest Group                          pean patents. He is an associate editor of IEEE
                              on Data Communication, Best of Computer                              Transactions on Mobile Computing and IEEE
                              Communication Review session. He is a Mem-                           Transactions on Cloud Computing and a guest
                              ber of IEEE. Further information about him can                       editor of IEEE Communications Magazine. He
                              be found at http://homepage.tudelft.nl/8e79t/.                       is a Fellow of IEEE and an ACM distinguished
                              Contact him at aaron.ding@tudelft.nl.                                scientist. Further information about him can be
                                                                                                   found at https://www.cs.helsinki.fi/u/panhui/.
                                                                                                   Contact him at panhui@cs.helsinki.fi.

                              YU XIAO is an assistant professor in the
                              Department of Communications and Network-
                              ing, Aalto University, Espoo, 02150, Finland,
                              where she leads the mobile cloud computing
                              group. Her research interests include edge
                              computing, mobile crowdsensing, and energy-
                              efficient wireless networking. Xiao received
                              her doctoral degree in computer science
                              with distinction from Aalto University. Further
                              information about her can be found at https://
                              people.aalto.fi/yu_xiao. She is a Member of
                              IEEE. Contact her at yu.xiao@aalto.fi.

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FEATURE: ONLINE DEVELOPER COMMUNITY

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