Limitations
That a large proportion (77.6%) of participants did not author prompts highlights that we cannot be sure that the dataset we obtained is representative of all participants from the parent trial. The risk of selection bias is an important study limitation because, in addition to the observed differences, those who chose to use the prompts module may be different from those who did not in unmeasured ways. It should also be noted that individuals in the control group represented here are likely to be those who are highly motivated to change their drinking behaviour, since they engaged with the support tool even after being on a waiting list for 4 months.Some of the prompts were single words and somewhat difficult to code due to lack of context: many of the 88 prompts that remained uncoded were single words. To minimise over-interpreting the data, such short prompts were rarely assigned codes such as Finally, relationships between prompt behaviour (being a prompt engager or not, the type of prompts written etc.) and changes in drinking behaviour were not examined here because, although this would be an interesting line of research, the exploratory nature of the present work is not the ideal platform for such an endeavour. This is because the direction of any relationships detected would be ambiguous (does writing a prompt affect alcohol behaviour, or does a change in alcohol behaviour affect the type of prompt written), and any number of unmeasured variables could lead to erroneous inference. Instead, an experimental approach where individuals are randomized to produce prompts of varying themes/types would be more appropriate to investigate this, so that other factors could be adequately controlled for (e.g., demographics, baseline drinking behaviour etc.)