A factorial, cluster randomised trial of an enhanced associate principal investigator (API) training package and an additional digital nudge delivered by a trial coordinator

The primary objective is to assess the effects of an enhanced API package, a digital nudge, and a combination of the two compared to standard practice API and/or standard email alone on the number of patients recruited to the host trial during the six months that the API is in post at a recruiting site.

Secondary objectives include assessing the effects of the enhanced API package, digital nudge, and combination of the two on the number of patients recruited to the host trial over
12 months (six months of the enhanced API training package/standard practice API /digital email nudge/standard email only and six months after this) at a recruiting site; determining the time taken to implement each intervention; comparing the proportion of eligible participants who are recruited; determining the amount of time taken by the trial coordinators to deliver the enhanced API package and describing the methods of additional contact for peer support of the APIs.