Table 1.

Sample Sizes, Response Rates, Item Nonresponse Rates, and Costs by Experimental Groups.

	Experimental Groups
	Group $5/$5	Group $5/$10	Group $10/$0	Group $10/$5	Group $10/$10	Total
Sample Sizes
N	300	300	300	300	300	1,500
Not eligible	3	5	0	0	0	8
Completed surveys
After initial mailing	88	112	102	108	125	535
After second mailing	129	149	124	140	158	700
After final mailing	145	171	131	156	176	779
Response Rates (%)
After initial mailing	29.6	38.0	34.0	36.0	41.7	35.9
After second mailing	43.4	50.5	41.3	46.7	52.7	46.9
After final mailing	49.0	58.0	43.7	52.0	58.7	52.2
Item-missing Scores
Mean	0.020	0.021	0.016	0.022	0.012	0.018
Standard Deviation	0.050	0.065	0.038	0.048	0.026	0.047
Variable Costs
Incentives only	$2,540	$3,350	$3,000	$3,959	$4,690	$17,539
Total	$5,705	$6,363	$6,106	$6,988	$7,602	$32,764
Per completed survey	$39	$37	$47	$45	$43	$42