Table 1. SELECT Recruitment and Retention Strategies.

General strategy description	Specific SELECT application of this strategy
Recruitment Strategies
Establish study committees charged with monitoring recruitment and suggesting strategies to improve it as needed.	The SELECT Recruitment/Retention and Adherence Committee (RAC) and the Minority and Medically Underserved Subcommittee (MMUS) were established prior to the trial with the purpose of monitoring overall and minority recruitment and implementing strategies to increase recruitment of SELECT participants.
Study site selection	The study selected sites that would likely have a high proportion of eligible black participants, including the VA, which has had traditionally high black enrollment in its cooperative studies. (20)
Recruitment materials for physicians and lay public	Study branded recruitment materials were designed for promoting the study with physicians using scientific information and for the lay public using ninth grade or lower reading levels whenever possible.
Grants for recruitment activities	SELECT offered both Recruitment grants and Minority Recruitment Enhancement grants (19) designed to improve overall and minority recruitment.
Minority site training Workshops	Small interactive workshops for selected Principal Investigator and staff that focused on existing and new accrual strategies. (18)
Retention Strategies
Establish study committees charged with monitoring retention and suggesting strategies to improve it as needed.	The SELECT RAC and MMUS were established prior to the trial with the purpose of monitoring overall and minority retention and implementing strategies to increase retention of SELECT participants.
Site staff retention training	Site staffs attended semi-annual Workshops, which provided retention training. They could request mentoring visits to help increase site performance, including issues with retention.
Free Study Multivitamin	Participants and their partners were offered a free SELECT multivitamin, made without vitamin E or selenium, so they could continue taking a multivitamin while on SELECT (most commercial formulations contain vitamin E and selenium).
Participant newsletter	The SELECT Coordinating Center provided a semi-annual national newsletter which was available in English, French and Spanish. Study sites were encouraged to also provide a local newsletter.
Establish an advisory board comprised of study participants	Study sites had access to the SELECT National Participant Advisory Board (NPAB), whose members were available to attend events and provide a participant's perspective. NPAB members also appeared in motivation videos for sites to use.
Grants for retention activities	SELECT offered Adherence grants designed to improve retention.