$25 incentive (original N = 250) $50 incentive (original N = 250) P-value
Total completes 64 77
 
Cost
Incentives $6,250 $12,500 --
Mailings/paper supplies $3,620 $3,517 --
Overall $9,870 $16,017 --
Per complete $154.22 $208.01 --
 
Avg. no. of reminders 2.3 1.8 .029a
Mode of completion .220b
Online 88% 94%
Paper 13% 6%