The Effect of Cash Lottery on Response Rates to an Online Health Survey among Members of the Canadian Association of Retired Persons: A Randomized Experiment

ABSTRACT

Objectives: The objectives of the study were 1) to assess the effect of cash lottery on participation rates in a web-based study of physical activity and joint health and 2) to compare recruitment via direct e-mail versus advertisement in an online newsletter.

Methods: A sample of 1,150 individuals, randomly selected from a database of members of the Canadian Association of Retired Persons (CARP), was e-mailed a request to participate in an online survey, with follow-up e-mails after 1 and 2 weeks. The sample was randomly split into two groups. Half the sample was offered entry into a cash draw with a $500 grand prize and five $100 prizes, whereas the other half …