Table 1.

Sample, response, and response rates

	Incentive group	Control group
Sample	1 200	1 200
Sample after withdraws	1 161	1 145
Pre-reminder response	558	443
Pre-reminder response rate1	48.1%	38.7%
Reminder response	187	229
Reminder response rate1	187/603 = 31.0%	229/702 = 32.6%
Total response	745	672
Total response rate1	64.2%	58.7%

¹ Response rate after withdraws.