Table 2.

Randomized controlled trial characteristics and study quality

First author (ref.)Number of participants, baselineMean age CHW intervention participants, yMean age control participants, yLength of intervention, moTime from baseline to follow-up, moGeneration of randomization sequencePower analysisDescribed drop outsParticipants selected because of lack of adherenceDefinition and measurement of mammography outcomeITT analysis conducted
Allen (41)2,943NDND1630Work sites blocked on size of worksite and type of agency to create 4 blocks. Within each block random-number generator assigned work sites to each condition.NDYesNoPast 12–24 mo; self-reportNo
Anderson (42)8,907NDND243640 communities assigned to 10 blocks of 4 communities for block randomization. Each community within one of ten blocks randomly assigned to a study arm using one of 24 permutation patterns of 4 for each block.NDYesNoWithin 24 mo of follow up interview; self-reportNo
Calle (44)738NDND68American Cancer Society volunteers each generated list of 10 women. Lists collected and women randomized to either intervention or control groups.NDYesNoBecause start of intervention; self-reportNo
Duan (45)1,113NDND241230 churches matched to 12 blocks and randomized half the churches in each block to peer counseling and other half to control. Matching variables included race/ethnicity, membership size, resources, and denomination.NDYesNoPast 12 mo; self-reportNo
Margolis (50)1,65854.555.91 day plus mailed reminders12+Patients assigned to intervention or usual care according to whether medical record number was odd or evenNDYesNo12 or 24 mo (depending on age); self-report plus chart reviewYes
Paskett (56)89754.555.712–1412–14Stratified selection, blocked randomization by race and clinic, conducted by study statisticianYesYesYesPast 12 months; chart reviewNo
Slater (58)42768.967.4241241 public housing high rise buildings randomized to treatment or control groups. Buildings stratified based on number of women per building who were 40 years and older.NDYesNoWithin 15 mo of intervention; self-reportNo
Sung (60)321NDND1117Participants randomly assigned to intervention or control groupsNDYesNoDepended on age (within 4 y if 35–39; within 3 y if 40–49; yearly if older than 49); self-reportNo
Weber (61)376636347Patients randomized to one of two groups. Randomization stratified by practice siteYesYesYesDuring intervention period; chart reviewYes
West (63)320NDND1 day6Envelope containing randomization group opened by CHW after completing telephone interviewNDYesYesPast 6 mo; self-reportYes