Comparison of up-front cash cards and checks as incentives for participation in a clinician survey: a study within a trial

Table 3 Impact of providers’ city on the association between incentive type and likelihood of survey response

City	Survey responses among those receiving checks	Survey responses among those receiving cash cards	Adjusted OR for survey response with check versus cash card incentive (95% CI)^a
Boston	53.2%	57.1%	0.74 (0.33, 1.69)
New York	43.2%	41.9%	1.07 (0.44, 2.58)
Los Angeles	63.6%	25.7%	4.73 (1.65, 13.50)
Philadelphia	62.5%	35.7%	3.61 (1.11, 11.72)

^aUsing logistic regression with interaction terms for city and incentive type; ORs are adjusted for provider sex, type and specialty. Measure of effect modification by city: p = 0.02 using Wald Chi-square test

ISSN: 1471-2288