Recruitment by the use of mass mailings.

Mass mailing represents a moderate-volume, low-efficiency recruitment strategy with a relatively moderate volume of initial contacts and low volume of entries, a low ratio of entries to initial contacts, and a relatively moderate effort level requirement for the recruitment team. In the CPPT, this source provided 6% of initial contacts, 7% of first protocol visits and 6% of entries. Although seven centers used mass mailing, 65% of total entries from this source were accounted for by the Oklahoma LRC. Mailings were sent to those identified through voter registration and driver licensee lists, group membership and direct-mail services firms. Variable responses were obtained, with voter registrants yielding the highest level. Unwillingness to participate at the first protocol visit excluded only one-third as many participants from this source as was observed among all sources. Costs were significantly reduced by the availability to the center of computerized mailing lists, as well as the adoption of automated data processing procedures in conducting the mailings and follow-up phases.