Support in the UK for app-based contact tracing of COVID-19 - OSF
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Support in the UK for app-based contact tracing of COVID-19
Johannes Abeler1 , Sam Altmann, Luke Milsom, Séverine Toussaert, Hannah Zillessen
Department of Economics, University of Oxford
This version: 14th April, 2020
First version: 26th March, 2020
1 Summary
The COVID-19 pandemic is the greatest public health threat that Europe has seen in the
last 100 years. Countries have thus introduced various levels of “lockdown” to reduce the
number of new infections. Lockdowns, however, come at a great cost to workers, firms and
families. Recent epidemiological models also predict that the epidemic will start anew, once
the lockdown is lifted (e.g., Ferguson et al. 2020).
Scientists have thus discussed a second approach to keeping the epidemic in check: app-
based contact tracing (Feretti & Wymant et al. 2020). The idea is simple. People download
an app on their phone. The app uses Bluetooth technology (and possibly GPS data) to
register which other users of the app have been in close proximity for at least 15 minutes.
If an app user is diagnosed with the coronavirus, all people who have been recently in close
proximity to this person are notified immediately. They are advised to self-isolate at home
for 14 days or until they have been tested for the virus. All of this can be done while
preserving the privacy of users.2
App-based contact tracing is useful because people can infect others even before they
show symptoms of COVID-19. Early self-isolation would thus reduce the onward spread of
the virus. If used widely enough, an app of this type could control the epidemic without a
sustained nation-wide, and enormously costly, lockdown (Feretti & Wymant et al. 2020).
1
Corresponding author: johannes.abeler@economics.ox.ac.uk
2
For example, the app in Singapore only logs other users in close proximity and records a cryptographically
generated temporary user ID rather than any identifiable information. The data is stored locally on the user’s
phone. Then, if a user is flagged as COVID-19 positive, it sends alerts to all logged IDs, without revealing
the identities to other users.
1
Given these potential benefits, many countries are racing to develop such an app, includ-
ing the UK and Germany, or have already launched one, e.g., Singapore. However, many
unknowns remain around the acceptability of app-based contact tracing:
1. Overall support: Given the obvious privacy issues, would enough people install the
app for it to be useful? What is the general public’s view of such an app?
2. Barriers to adoption: What are people’s main reasons for, and against, installing
the app? How could the design and messaging around the app affect adoption?
3. Installation regime: How could different installation regimes, in particular, vol-
untary installation vs. automatic installation by mobile phone providers, affect the
number of installations?
To answer these questions, we conducted a survey with a large representative sample of the
UK population (1055 respondents) between the 20th and 22nd March 2020. Here are our
key findings:
1. There is wide support for app-based contact tracing.
◦ About three-quarters of respondents said they would definitely or probably install
the app. There is wide consensus regardless of a respondent’s gender, age, or region.
However, respondents who lack trust in the government are less favourable.
◦ The vast majority said they would definitely comply with the app’s advice to self-
isolate if a close contact had been infected. Early COVID-19 testing by the NHS
once in self-isolation further increases support.
◦ Most respondents state that their opinion of the UK government would improve if it
introduced such an app. Political affiliation has little effect on this response.
2. The main reasons against installation are (i) an increased risk of government surveil-
lance after the epidemic, (ii) that one’s anxiety about the epidemic would increase,
and (iii) fear of one’s phone being hacked.
3. A majority supports automatic installation (with an opt-out possibility).
◦ About three-quarters of respondents said they would probably or definitely keep the
app installed on their phone if it were automatically installed.
2
◦ Most respondents agreed that the government should ask mobile phone providers
to automatically install the app to maximise the chances of stopping the epidemic.
Opinion of the government would improve if such a policy were in place.
We have conducted this survey also in Germany, France and Italy and the US find very
similar results, see Figure 12 (the data and reports for all countries will be accessible here).
We discuss the policy implications of our results in Section 4. In brief, since app-based
contact tracing is more effective if many people install the app, our findings are encouraging
news for the prospects of this approach. The survey suggests that people are willing to
install the app and are willing to comply with the self-isolation request. If the design of
the app and the messaging around the launch of the app managed to alleviate fears about
future surveillance, about hacking, and in general reduce the anxiety around the epidemic,
we would expect the number of installations to increase.
The main caveat about our study is that we could only ask hypothetical questions about
future behaviour. The real decisions about installing the app might turn out differently.
Moreover, our survey does not address the legal and ethical implications of using such an
app (e.g., Feretti & Wymant et al. 2020). Nevertheless, our results provide some guidance on
the acceptability of app-based contact tracing and can inform both the design and framing
of a contact-tracing app.
2 Survey Design
We administered a 10-minute online survey between the 20th and the 22nd of March 2020 to
a sample of 1055 UK residents. The survey period was just before the school closures came
into effect and a further lockdown was announced (both on 23rd March). Respondents were
recruited via the online panel provider Lucid and selected to be representative of the adult
UK population on gender, age, region of residence, and employment status. We excluded
participants who didn’t own a mobile phone.
The survey started with a short description of the app, explaining how to install it,
what the app would do if one of your contacts were diagnosed with the virus and what the
app would do if you were diagnosed.3 The actual questionnaire consisted of four blocks of
questions. First, we asked respondents to consider the case in which people can voluntarily
3
Respondents had to correctly answer comprehension questions about the app in order to proceed to
the rest of the survey. Once the actual questionnaire was started, virtually no respondent dropped out (see
Figure 11 in the Appendix). See Appendix 5.1 for more details about the final sample.
3
install the app. We then asked respondents to think about the case in which the government
requests mobile phone providers to automatically install the app on all phones, with the
possibility to uninstall it. After some demographic questions, we finally asked how the two
cases described before would affect respondents’ views of the UK government. The entire
text of the survey is shown in Appendix 6.
Respondents recruited online might not be representative of the entire population in all
respects. For example, one might worry that technical literacy and willingness to share data
could be higher among such respondents. To make sure that our results are not driven by our
recruitment process, we replicated a shortened version of our German survey with a different
recruitment method. One week after the initial survey, we repeated our online survey twice,
once again with Lucid and also with Forsa. Although both surveys were conducted online,
Forsa, unlike Lucid, recruits its online panel members from a probability based, randomly
selected telephone sample.4 This offline recruitment process ensures that respondents are
more representative of the general population. We find almost exactly the same results in
the replication surveys, alleviating concerns about our original sample (see Figure ?? in the
Appendix). More details about the replication can be found in the German country report.
3 Results
Result 1 There is wide support for app-based contact tracing.
We asked respondents about their likelihood of installing (or not) the app on their phone.
They could answer on a five-item scale from Definitely install to Definitely won’t install.5
Figure 1 contains the results. The first bar from the left shows that 73.6% of respondents
would definitely or probably install the app. There is wide consensus about installation
regardless of a respondent’s gender or age (see Figures 7 and 8 in the Appendix). However,
respondents who trust the government less are less likely to install the app (see Figure 9 in
the Appendix).
To understand how the decision to install might change as the epidemic evolves and the
lockdown measures become more stringent, we asked respondents who did not already say
they would definitely install the app about their likelihood of installing it in the following
4
To recruit participants, Forsa randomly generates phone numbers, calls the respective households and
invites them to participate in the survey. Due to the direct contact over the phone, the sample should contain
neither bots, nor respondents with a dubious identity (due to fake identities or multiple sign-ups).
5
Respondents could also select the option “I don’t know”. In the results, we merge this option with the
middle option “May or may not install”.
4
Figure 1
three scenarios:
1. Someone in their community is infected by the virus.
2. Someone they know personally is infected by the virus.
3. A full lockdown as in Italy is introduced by the UK government, but the restrictions
are lifted for those who have an app that shows an “all clear” message.
We find that the likelihood of installing the app increases in all three scenarios, particularly
in the lockdown scenario (see Figure 1) where 84.3% of respondents would definitely or
probably install the app. This suggests that support for the app will likely grow as the
epidemic progresses.
Result 2 The vast majority of respondents would definitely comply with the app’s advice to
self-isolate if a close contact had been infected. Early testing by the NHS once in self-isolation
further increases support.
5
Figure 2
We asked respondents how likely they would be to comply with the recommendation of
self-isolating for 14 days if they had been in close contact with a person infected (Definitely
comply - Definitely won’t comply). Those who did not select Definitely comply were then
asked whether their chances of compliance would increase, decrease, or remain the same
if they could be tested for the virus by the NHS within two days from the start of their
self-isolation (a negative test allowing them to stop self-isolating).
As Figure 2 shows, 91.5% would definitely or probably comply with isolation. Among those
who would not definitely comply, 62.6% said they would be more likely to comply if the
government offered them a test rapidly. Thus, respondents overwhelmingly agree with the
principle behind the app and are ready to comply with its recommendations.
Result 3 Most respondents stated that their opinion of the UK government would improve
if it introduced such an app. Political affiliation had little effect on their response.
We asked respondents to what extent they agreed, or not, with the following statement:
“My opinion about the British government would improve if they introduced such an app
and allowed me to decide myself whether to install it or not.”
6
Figure 3
As shown by the left-most bar in Figure 3, only 12.8% of respondents said their opinion of
the government would worsen, while 55.2% of respondents said their opinion would improve.
Answers are remarkably similar irrespective of the political leanings of the respondents, as
the bars on the right of Figure 3 show.
Result 4 The main reasons against installation are (i) an increased risk of government
surveillance after the epidemic, (ii) that one’s anxiety about the epidemic would increase,
and (iii) fear of one’s phone being hacked.
We asked respondents about their main reasons for and against installing the app. In both
cases, respondents could select up to 5 reasons from a menu of options or name their own
reasons (the order of options was randomized). Figure 4 shows the main reasons against
installing the app. Respondents are most concerned about the “government using the app
as an excuse to increase surveillance after the epidemic”. They are also concerned that the
app would “make them feel more anxious” and that their “phone might get hacked”.
As Figure 5 shows, the main reason given for installing the app was to “protect family and
7
Figure 4
friends”, but “responsibility to the community”, “might stop the epidemic” and “lets me
know the risk of infection” are also often named.
Figure 5
8
Older respondents worry more about their phone being hacked and less about government
surveillance. Otherwise, the reasons given do not appear to depend much on a respondent’s
age, gender, or willingness to install the app.
Result 5 A majority supports automatic installation (with an opt-out possibility).
We also asked respondents to consider an automatic installation policy: the government
would require mobile phone providers to automatically install the app on all phones, but users
would be able to uninstall the app at any time. We explained that this would maximise the
chance of stopping the epidemic. Respondents stated their chances of keeping or uninstalling
the app in this case (Definitely keep - Definitely uninstall ). As shown in Figure 6, 72.3% of
respondents said they would definitely or probably keep the app on their phone.
To further understand public support for automatic installation, we then asked respondents
to indicate whether they thought the government should implement such a policy. The right
bars in Figure 6 show that 68.6% thought the government should do so. This share rises
slightly if we ask those who did not agree completely with the approach, about their stance
once someone in their community or someone they know has been infected. We also asked
whether their opinion of the government would change if such a policy were in place. Most
respondents said this would improve their opinion, independent of their political leaning
(Figure 10 in the Appendix).
Result 6 A large majority of respondents would prefer to make the collected data available
for research purposes after the end of the pandemic.
We asked respondents what should happen to the collected data after the end of the pan-
demic: automatically delete all data, de-identify the data and make it available for research
purposes, or some other option of their choice. 64.6% preferred to make the data available
for research purposes.
9
Figure 6
4 Policy implications
Since app-based contact tracing is more effective if many people install the app, our findings
are encouraging news for the prospects of this approach.
Our study suggests that the public would be open to both a voluntary (opt-in) and
an automatic (opt-out) installation policy.6 There are obvious trade-offs between the two
policies. An automatic installation would probably lead to higher adoption rates, e.g., by
reducing transaction costs. However, such an installation policy is much more intrusive and
it remains to determine how it could be implemented in a way that respects the current laws
(for more on the ethical implications see, e.g., Feretti & Wymant et al. 2020).
The main reasons cited against an installation are concerns about future government
surveillance, fear of getting hacked and increased anxiety. The app should be developed in
a way that clearly addresses those concerns. Technically, one could avoid the use of GPS
data and only rely on the Bluetooth technology (as in Singapore). Organisationally, a highly
reputable and transparent authority, at arms-length from the government, would increase
6
We only asked about three installation regimes (voluntary, voluntary but the app gives extra rights
to exit the lockdown, automatic installation with opt-out). Other intermediate steps could be taken. For
instance, the government could ask mobile phone providers to send a text message containing the link to
the app (as was done on the 24th of March to provide self-isolation advice), or ask mobile phone providers
to pre-install the app but directly ask all users whether they want to keep it (opt-in) or not.
10trust. Concerns about government surveillance may speak against the more intrusive auto-
installation.
The main caveat about our study is that we could only ask hypothetical questions about
future behaviour and could only discuss the app in general terms. Our online panel respon-
dents might also be more willing to share data than the general population. So even if 75% of
our respondents said they would install the app, it does not mean that such a large fraction
of people will actually do so. Factors such as unawareness and procrastination mean that
the actual share of installations will not entirely reflect people’s true willingness to install
the app. For instance, Singapore adopted a voluntary installation regime and launched a
strong marketing campaign; however, about two weeks after the launch, the penetration rate
of the app remains under 25%. This speaks for an auto-installation regime.
We find strong support for the app concept across four large European countries. This
points to the possibility of a pan-European app for which development resources could be
pooled, and which could allow for roaming across countries.
Looking ahead, our study also suggests that the public would be very favourable to
sharing the collected data with university researchers to prepare for future pandemics.
115 Appendix: Further results
Figure 7
Figure 8
12Figure 9 Figure 10 13
Figure 11 Figure 12 14
Figure 13 15
5.1 Appendix: Demographics
Respondents (%)
EN-GB
Age: 18-30 20.3
31-40 20.2
41-50 21.4
51-60 18.7
61-70 13.8
71-80 5.2
Older than 80 0.4
Gender: Female 48.0
Male 51.1
Other 0.5
Prefer not to say 0.4
Region: London 14.5
England not Lnd. 69.0
Wales 5.3
Scotland 8.9
N. Ireland 2.4
Health Problems: Yes 29.4
No 70.6
Employed: Yes 69.7
No 30.3
Observations 1055
Health Problems refers to diabetes, asthma, high blood pressure, heart or breathing problems.
166 Appendix: Survey text
17Qualtrics Survey Software https://econresearch.eu.qualtrics.com/Q/EditSection/Blocks/Ajax/GetS...
In this study, we will ask you about an app that could help reduce the spread of the
COVID-19 epidemic. You may ask any questions before deciding to take part by
contacting the researchers (details below). The survey is about 10 minutes long. No
background knowledge is required.
Do I have to take part?
Please note that your participation is voluntary. If you do decide to take part, you
may withdraw at any point during the survey for any reason before submitting your
answers by closing the browser.
How will my data be used?
Your answers will be completely anonymous. Your data will be stored in a password-
protected file and may be used in academic publications. Research data will be
stored for a minimum of three years after publication or public release.
Who will have access to my data?
Lucid is the data controller with respect to your personal data and, as such, will
determine how your personal data is used. Please see their privacy notice
here: https://luc.id/privacy-policy/. Lucid will share only fully anonymised data with
the University of Oxford, for the purposes of research. Responsible members of the
University of Oxford and funders may be given access to data for monitoring and/or
audit of the study to ensure we are complying with guidelines, or as otherwise
required by law.
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This project has been reviewed by, and received ethics clearance through, the
University of Oxford Central University Research Ethics Committee (reference
number ECONCIA20-21-06).
Who do I contact if I have a concern about the study or I wish to complain?
If you have a concern about any aspect of this study, please contact Johannes
Abeler at johannes.abeler@economics.ox.ac.uk and we will do our best to answer
your query. We will acknowledge your concern within 10 working days and give you
an indication of how it will be dealt with. If you remain unhappy or wish to make a
formal complaint, please contact the Chair of the Research Ethics Committee at the
University of Oxford who will seek to resolve the matter as soon as possible:
Economics Departmental Research Ethics
Committee at ethics@economics.ox.ac.uk
Please note that you may only participate in this survey if you are 18 years of
age or over.
If you have read the information above and agree to participate with the
understanding that the data (including any personal data) you submit will be
processed accordingly and that you need to be 18 years of age or over
to participate, please confirm below.
I confirm
I do not confirm
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Permission to use my location data
Permission to access my photos
Permission to access my WhatsApp contacts
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Ask me to self-isolate
Give me an "all clear" message
Tell me the name of the person who was diagnosed
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Give my name and address to all people I have been in close contact
with
Advise all people I have been in close contact with to self-isolate
Shut down my phone
Definitely install
Probably install
May or may not install
Probably won't install
Definitely won't install
Don't know
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It would let me know my risk of being infected
It would help me stay healthy
It would protect my family and friends
Seeing the "all clear" message would give me peace of mind
A sense of responsibility to the wider community
It would help reduce the number of deaths among older people
It might stop the epidemic
Other (please indicate in the field below):
I won’t be infected anyway
The app would be too much hassle to install
I would not benefit from the app
I worry that my phone will be more likely to get hacked
I worry the government would use this as an excuse for greater
surveillance after the epidemic
I don't want to feel more anxious than I already feel
I don't want the NHS to have access to my location data
Other (please indicate in the field below):
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Definitely comply
Probably comply
May or may not comply
Probably won't comply
Definitely won't comply
Don't know
More likely
Equally likely
Less likely
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Definitely install
Probably install
May or may not install
Probably won't install
Definitely won't install
Don't know
Definitely install
Probably install
May or may not install
Probably won't install
Definitely won't install
Don't know
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Definitely install
Probably install
May or may not install
Probably won't install
Definitely won't install
Don't know
Definitely keep
Probably keep
May or may not keep
Probably uninstall
Definitely uninstall
Don't know
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Fully agree
Somewhat agree
Neither agree nor disagree
Somewhat disagree
Fully disagree
Fully agree
Somewhat agree
Neither agree nor disagree
Somewhat disagree
Fully disagree
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Fully agree
Somewhat agree
Neither agree nor disagree
Somewhat disagree
Fully disagree
All data will be automatically deleted at the end of the epidemic and not
used for any other purpose
All data will be de-identified and made available to university
researchers to prepare for future epidemics
Other (please indicate in the field below):
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18-30
31-40
41-50
51-60
61-70
71-80
Older than 80
Female
Male
Other
Prefer not to say
London
England not including London
Wales
Scotland
Northern Ireland
Not more than once per week
A few times per week
A few times per day
Many times per day
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Yes
No
Always
Most of the time
Sometimes
Rarely
None of my normal work
About a quarter of my normal work
About half of my normal work
About three quarters of my normal work
All of my normal work
I do not work or study
Yes
No
Don't know
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Liberal Democrats
Labour
Conservatives
SNP
Brexit Party
Plaid Cymru
Other or I don't want to say
Fully agree
Somewhat agree
Neither agree nor disagree
Somewhat disagree
Fully disagree
Fully agree
Somewhat agree
Neither agree nor disagree
Somewhat disagree
Fully disagree
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Fully agree
Somewhat agree
Neither agree nor disagree
Somewhat disagree
Fully disagree
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