Interviews were conducted with 31 TREC I participants (Table 1).They included the director of each of the four TREC I research centers; the PIs of one or two of the primary research subprojects at each research center; and PIs of developmental pilot projects conducted at all four research centers and across centers, who also held roles as primary research subproject PIs, junior investigators, and postdoctoral trainees. Interview participants also included biostatistics core staff at all four research centers and training core directors at three of the research centers. Some training core directors also held roles as research center directors or primary subproject PIs. Finally, interview participants included two or more trainees from each center and three staff of the TREC I coordination center, including the director.
