Analysis of the factors affecting the adoption and compliance of the NHS COVID-19 mobile application: a national cross-sectional survey in England.

Objectives: To conduct an independent study investigating how adults perceive the usability and functionality of the 'National Health Service (NHS) COVID-19' application (app). This study aims to highlight strengths and provide recommendations to improve adoption of future contact tracing developments.

Design: A 60-item, anonymous online questionnaire, disseminated through social media outlets and email lists by a team from Imperial College London.

Setting: England.

Participants: Convenience sample of 1036 responses, from participants aged 18 years and above, between December 2020 and January 2021.

Primary Outcome Measures: Evaluate the compliance and public attitude towards the 'NHS COVID-19' app regarding its functionality and features. This included whether participants' expectations were met, and their thoughts on the app privacy and security. Furthermore, to distinguish how usability, perception, and adoption differed with varying demographics and user values.

Results: Fair compliance with the app features was identified, meeting expectations of the 62.1% of participants who stated they downloaded it after weighted analysis. However, participants finding the interface challenging were less likely to read information in the app and had a lesser understanding of its functionality. Furthermore, little understanding regarding the app's functionality and privacy concerns was a possible reason why users did not download it. A readability analysis of the text revealed information within the app was conveyed at a level that may be too complex for up to 43% of the UK population. The study highlighted issues related to the potential of false positives caused by the design choices in the 'Check-In' feature.

Conclusion: This study showed that while the 'NHS COVID-19' app was viewed positively, there remained issues regarding participants' perceived knowledge of app functionality, potentially affecting compliance. Therefore, we recommended improvements regarding the delivery and presentation of the app's information, and highlighted the potential need for the ability to check out of venues to reduce the number of false positive contacts.