From: Differential effects of pre and post-payment on neurologists' response rates to a postal survey
Incentive | First Round (300 replies) | Second Round (51 replies) | Aggregate (351 replies, 59%) |
---|---|---|---|
Token Sent (n = 214) | 131/214 (61%) | 20/83 (24%) | 151/214 (71%) |
Token Promised (n = 147) | 71/147 (48%) | 8/76 (11%) | 79/147 (54%) |
No Token (n = 230) | 98/230 (43%) | 23/132 (17%) | 121/230 (53%) |
Difference | p = 0.0004 | p = 0.08 | p = 0.0002 |