Trials within trials? Researcher, funder and ethical perspectives on the practicality and acceptability of nesting trials of recruitment methods in existing primary care trials

Table 1 Summary of potential recruitment interventions provided to participants before interview

	Unit of Allocation¹	Recruitment Stage²	Type of Intervention
Financial incentives to patients and professionals (e.g. payment for recruitment, lottery etc)	Trial, cluster, individual	1, 2, 3, 4	Incentives
Attachment of additional, dedicated research nurses for sessions in participating centres	Trial	2, 3, 4	Resources
Showing a DVD of previous trial participants discussing their experiences of being involved in research.	Cluster, individual	1, 2, 3	Attitudes of patients and professionals
Mass media approaches to change attitudes to trials among patients	Trial	3, 4	Attitudes of patients
Educational incentives to clinicians. e.g. seminar on trials and research methods	Trial, cluster	1, 2	Attitudes of professionals
Training for clinicians in seeking consent for trials	Trial, cluster	2	Attitudes of professionals
Option to refer patients to a dedicated research centre or hub	Trial, cluster	2	Incentives for professionals
Support for investigators on project management and monitoring approaches, with in-built contingency planning	Trial	Trial planning	Advice and support for trial recruitment

¹ Unit of allocation for the recruitment intervention: (Trial, Cluster within a trial, Individual patient)
² Recruitment stage that intervention is designed to improve:
Trial planning and organization;
Stage 1: Professional consent to participate in trial;
Stage 2: Professional recruitment of patients;
Stage 3: Patient consent to participate in trial;
Stage 4: Retention of patient in trial

ISSN: 1471-2288