Table 1 Inclusion and exclusion criteria

Study design

Any primary study design that investigates the recruitment to RCTs in general practice. Qualitative, quantitative and mixed methods studies were included.

Participants

Any participants, both where the focus was on recruitment of practices to RCTs as well as recruitment of individual patients.

Interventions

Any interventions that target recruitment.

Comparators

Any comparators were included.

Outcomes

Outcomes that are focused on recruitment. Examples of outcomes include the number of participants recruited, percentage of recruitment target achieved and time to the first participant recruited.

Setting

The study investigating recruitment must be of any RCT that is set within general practice, i.e. general practices are the locus of the intervention where recruited participants are randomised to an intervention based on the practice.

Language

Only studies in English were included.