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Table 3 Cost per subject who completed baseline and follow-up interviews

From: The effect of timing of incentive payments on response rates for cohort study telephone interviews in primary care setting with cost-minimization analysis, a randomized controlled trial

  Up-front payment Delayed payment
Resource component Unit cost (USD) n n X unit cost (USD) n n X unit cost (USD)
Incentive
 Coupon 6.50 360 2340 205 1332.50
Staff
 Baseline interviewa 2.18 259 565.66 260 567.84
 12-month interview 2.18 201 438.98 205 447.72
 Administrative work for payment at 12-monthb 1.82 0 0.00 205 373.10
Stationary
 Letter to patient at 12-month 0.01 0 0.00 205 1.68
 Postage 0.44 0 0.00 205 90.61
 Two envelopes 0.12 0 0.00 205 25.05
Total cost (USD) 3344.64   2838.50
Number of subjects successfully contacted at 12 months 201   205
Cost (USD)/successful subject at 12 months 16.64   13.85
  1. aCalculation was based on 12 mins/subject to process each incentive payment and an administrative staff cost of 10.9 USD
  2. bCalculation was based on 10 mins/subject to process each incentive payment and an administrative staff cost of 10.9 USD