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Currently submitted to: JMIR Research Protocols

Date Submitted: Mar 12, 2020
Open Peer Review Period: Mar 12, 2020 - May 7, 2020
(currently open for review)

Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.

NOtifications To improve Engagement (NOTE) with an alcohol reduction app: protocol for a micro-randomised trial

  • Lauren Bell; 
  • Claire Garnett; 
  • Tianchen Qian; 
  • Olga Perski; 
  • Henry W W Potts; 
  • Elizabeth Williamson; 



Drink Less is a behaviour change app which aims to help users in the general adult population reduce hazardous and harmful alcohol consumption. The app includes a daily push notification, delivered at 11am, asking users to “Please complete your mood and drinking diaries”. Previous analysis with Drink Less engagement data suggests the current notification strongly influences how users engage with the app in the subsequent hour of delivery, and patterns of engagement fluctuate over the course of the day, with an increase in frequency and duration of use observed between 8pm to 10pm. We aim to improve engagement by exploring the content and sequence of notifications delivered at 8pm, where we will test a bank of 30 new evidence-informed notifications which intend to increase the user’s perceived usefulness of the app.


The primary objective is to assess if sending a notification at 8pm increases behavioural engagement in the subsequent hour. Secondary objectives include comparing the effect of the new bank of messages with the standard message and effect moderation over time. We also aim to more generally understand the role notifications have on the overall duration, depth and frequency of engagement with Drink Less over 30 days since download.


This is a protocol for a micro-randomised trial with two parallel arms. The parallel arms include receiving no notifications (Secondary Arm A), and users receiving the standard notification “Please complete your mood and drinking diaries”, delivered daily at 11am (Secondary Arm B) over 30 days. Inclusion criteria include: users who i) consent to participate in the trial; ii) self-report a baseline Alcohol Use Disorders Identification Test (AUDIT) score of 8 or above; iii) reside in the UK; iv) are aged 18+ years and; v) report being interested in drinking less alcohol. The primary outcome is the time-varying, binary outcome of “Did the user login in to the app in the hour from 8pm to 9pm?”. The primary analysis will measure the marginal effect of the notifications, quantified as a relative risk with a 95% confidence interval, using an estimator developed for micro-randomised trials with binary outcomes. The parallel arms will allow us to compare the effect of different notification delivery strategies on overall engagement.


Ethical approval was granted by UCL’s Departmental Research Ethics Committee (CEHP/2016/556) on 11th October 2019 and LSHTM’s Interventions Research Ethics Committee (17929) on 27th November 2019. Recruitment began on the 2nd January 2020 and is currently ongoing.


Understanding how push notifications may impact engagement with a behaviour change app can lead to further improvements in engagement, and ultimately help users reduce their alcohol consumption. This understanding may also be generalisable to other apps that target a variety of behaviour changes.


Please cite as:

Bell L, Garnett C, Qian T, Perski O, Potts HWW, Williamson E

NOtifications To improve Engagement (NOTE) with an alcohol reduction app: protocol for a micro-randomised trial

JMIR Preprints. 12/03/2020:18690

DOI: 10.2196/preprints.18690


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