title: Combining conditional and unconditional recruitment incentives could facilitate telephone tracing in surveys of postpartum women.
abstract: OBJECTIVE
  To compare tracing and contact rates using alternative incentives in a computer-assisted telephone interview (CATI) survey among postpartum women.
  
  
  METHODS
  In a randomized trial of 1,061 postpartum women 18-49 years of age selected from four Iowa counties, we compared the effects of: (1) unconditional $5 telephone card incentive enclosed with the introductory letter followed by $25 incentive conditional upon successful telephone tracing, contact, and completion of CATI (Group 1, n = 530) vs. (2) $30 incentive conditional upon subject completion of CATI (Group 2, n = 531).
  
  
  RESULTS
  Overall telephone tracing and contact rates achieved were 67.8% and 66.6%, respectively. Tracing (70.2 vs. 65.4%, P = .09) and contact (68.5 vs. 64.8%, P = .26) rates were consistently higher among subjects assigned the combination of a conditional and an unconditional incentive. The combined incentive type had a greater impact on telephone tracing success rates for subjects on whom we could not initially locate an active telephone number (16.7 vs. 7.3%, P = .07) when compared to subjects for whom we found an active telephone number at the time of mailing the introductory letter (78.9 vs. 75.9%, P = .30).
  
  
  CONCLUSIONS
  Combining conditional and unconditional recruitment incentives can facilitate telephone tracing efforts in surveys conducted among recently postpartum women.
authors.affiliation: Department of Epidemiology, College of Public Health, University of Iowa, Iowa City, IA 52242, USA.
authors.forename: Hind
authors.initials: H
authors.lastname: Beydoun
authors.forename: Audrey F
authors.initials: AF
authors.lastname: Saftlas
authors.forename: Kari
authors.initials: K
authors.lastname: Harland
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Triche
mesh_terms: D003625:Data Collection / Q000379:methods*; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D009042:Motivation; D018579:Patient Selection; D049590:Postpartum Period; D011247:Pregnancy; D012494:Sampling Studies