Garnett, C;
Michie, S;
West, R;
Brown, J;
(2019)
Updating the evidence on the effectiveness of the alcohol reduction app, Drink Less: using Bayes factors to analyse trial datasets supplemented with extended recruitment [version 2; peer review: 2 approved].
F1000Research
, 8
, Article 114. 10.12688/f1000research.17952.2.
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Abstract
Background : A factorial experiment evaluating the Drink Less app found no clear evidence for main effects of enhanced versus minimal versions of five components but some evidence for an interaction effect. Bayes factors (BFs) showed the data to be insensitive. This study examined the use of BFs to update the evidence with further recruitment. Methods : A between-subject factorial experiment evaluated the main and two-way interaction effects of enhanced versus minimal version of five components of Drink Less. Participants were excessive drinkers, aged 18+, and living in the UK. After the required sample size was reached (n=672), additional data were collected for five months. Outcome measures were change in past week alcohol consumption and Alcohol Use Disorders Identification Test (AUDIT) score at one-month follow-up, amongst responders only (those who completed the questionnaire). BFs (with a half-normal distribution) were calculated (BF<0.33 indicate evidence for null hypothesis; 0.33<BF<3 indicate data are insensitive). Results : Of the sample of 2586, 342 (13.2%) responded to follow-up. Data were mainly insensitive but tended to support there being no large main effects of the enhanced version of individual components on consumption (0.22<BF<0.83) or AUDIT score (0.14<BF<0.98). Data no longer supported there being two-way interaction effects (0.31<BF<1.99). In an additional exploratory analysis, participants receiving four of the components averaged a numerically greater reduction in consumption than those not receiving any (21.6 versus 12.1 units), but the data were insensitive (BF=1.42). Conclusions : Data from extended recruitment in a factorial experiment evaluating components of Drink Less remained insensitive but tended towards individual and pairs of components not having a large effect. In an exploratory analysis, there was weak, anecdotal evidence for a synergistic effect of four components. In the event of uncertain results, calculating BFs can be used to update the strength of evidence of a dataset supplemented with extended recruitment.
| Type: | Article |
|---|---|
| Title: | Updating the evidence on the effectiveness of the alcohol reduction app, Drink Less: using Bayes factors to analyse trial datasets supplemented with extended recruitment [version 2; peer review: 2 approved] |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.12688/f1000research.17952.2 |
| Publisher version: | https://doi.org/10.12688/f1000research.17952.2 |
| Language: | English |
| Additional information: | This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
| Keywords: | Bayes Factors, digital interventions, alcohol reduction, smartphone apps |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Div of Psychology and Lang Sciences > Clinical, Edu and Hlth Psychology UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Epidemiology and Health UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Epidemiology and Health > Behavioural Science and Health |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10078585 |
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