Skip to main content

Table 2 Details of control selection for each sub-study

From: Recruiting and motivating black subjects to complete a lengthy survey in a large cohort study: an exploration of different strategies

Sub study Type of control Number of controls/Intervention units Timing of control period compared to intervention
A. Associated with baseline promotion
  Black Art Alone compared to $10 Other churches* 24/19 Concurrent
  Black Art + $10 compared to $10   24/62 Concurrent
B. Early post-baseline
  Telephone follow-up Other churches (randomized) 13/27 Concurrent
C. Mid post-baseline
  Operation 30,000 Self (152 churches) N/A 71 churches before and 81 after intervention period§
  Student recruiters Other matched churches 9/36 Concurrent
  Local Recruiters Other matched churches 12/10 Concurrent
  Tournament of Healing Other matched churches 22/38 Concurrent
D. Late post-baseline
  Lake Union $20 Self (80 churches) N/A All controls are an average of periods before and after intervention
  Enroll Another $2 bill None 0/500 N/A
  Enroll Another $10 None 0/500 N/A
  1. *Adjusted also for church size in the statistical model.
  2. These studies are individual subject, rather than church-based.
  3. §Likelihood weighted to restore balance.