Table 1. How the three phases of the refinement process relate to changes to app modules.

App module	Phase 1			Phase 2		Phase 3
	Factorial screening trial	Update of evidence review	User feedback	Public involvement through an Alcohol Discussion Group	Consultation with app designers, developers and researchers	User testing
Behavioural Substitution		Add (original Cochrane Review).		The plans added to be linked to their normal phone calendar. *	Need to reduce amount of text on screen with basic minimal layout.	Positive feedback. Clearer instructions on how to add an alternative plan and why to make one. Longer list of possible options to choose between. Be able to pick multiple options per day. *
Information about Antecedents		Add (updated review).		Did not like the name ‘Drinking triggers’ and would prefer ‘cues’.	Reduce amount of text on screen and simplify.	Positive feedback. Further details explaining the purpose of the module. How it related to other modules – link it to action planning.
Insights			Wanted running totals for alcohol units consumed.	Want a more detailed summary of feedback weekly and/or monthly.	Drop-down menu for different time periods for ‘My Average Week’.	Positive feedback. Preferred the average week graph as a bar graph and for lifetime totals section to be represented in ‘numbers and words’.
Identity Change	Remove.
Normative Feedback	Retain.		Wanted the ability to update their data used in the normative feedback.	Wanted more information on the data used for the normative feedback and the credibility of this information.	User to be able to update every 28 days. Have a home page with a gauge showing their original and latest scores. List of individual dates below this linking to full normative feedback for that score.	Positive feedback. Surprised by the normative feedback and questioned its credibility. Wanted more information in terms of what the normative feedback and AUDIT feedback meant as they found the wording confusing.
Self-Monitoring and Feedback	Retain.		Wanted calendar week to start on Monday. Not clear how to navigate to drinking calendar. Not clear how to navigate to mood diary. Unsure how to edit or delete drinks entries. Wanted to be able to add customisable volumes. Unclear that you can edit the default settings when adding a new drink. Bug fixes for drinks entry when time zone changed and when clocks went back.		Add an ‘Edit’ button in the top menu bar that when tapped mirrors the ‘delete’ widget in iOS; and add two large save/delete buttons at the bottom of the drinks screen. Start with default setting with the custom option as the last on the drop-down list with user typing in new volume. Any custom volumes added then added to the drop-down list.	Positive feedback. Unsure of how to add a mood diary for the first time. Did not realise that you could edit the type, volume or alcohol by volume (ABV) and that there were drop-down lists. Wanted to know how many calories in a typical drink.
Goal Setting						Positive feedback. How to set a new goal and how to edit existing ones. Did not realise that they could change the type of goal; wanted it to be clearer that there was a drop-down list. Wanted a direct link from goal setting page to drinking guidelines as they were not clear why the default was ‘14’ for the units goal.
Cognitive Bias Re-training	Retain.		Wanted any sugary or fizzy drink images removed from the game.	Wanted the images of sugary drinks to be removed from the game.		Positive feedback. Instructions to be briefer with less text on the first screen.
Action Planning	Retain.					Positive feedback. Your action plans shown on the dashboard. *
Navigational Structure						Difficulty with navigation across the app. Unclear what the difference between the progress and dashboard screens was.
Dashboard						Wanted drinking guidelines easier to find. Suggested list of tasks didn’t make sense as Drink + Me no longer an option.
Onboarding						Needed guidance during onboarding; found the three-step process confusing. Make the link to the infographic on alcohol units more prominent as did not notice it initially.
General			Android OS version of the app. * International availability. * Making the app accessible for individuals with red-green colour blindness. General Data Protection Regulation 2018 changes.	Wanted even less text on the app generally. Tailored reminders. *		Positive feedback. Not clear what the drinking guidelines are or what a unit is.

^*Changes not implemented due to budget restrictions.