The purpose of this paper will be to summarize the results of a series of ongoing, randomized experiments undertaken by Harris Interactive in 2001-02 to understand the effect of various stimuli on the survey participation rates of members of the Harris Poll Online (HPOL), the company’s panel of confirmed-opt-in online survey respondents. A second goal will be to connect these findings to the existing literature.
The stimuli used in the experiments include:
· The size and number of cash sweepstakes entries as incentives
· The size, number, and rate of accumulation of non-monetary rewards (referred to as HIpoints)
· Text versus HTML survey invitations
· Subject line content
· Personalization of the “from” line in email invitations
· Survey invitation content
Some of the major findings include:
· Confirmed opt-in members of HPOL who were offered an entry into a large cash sweepstakes (referred to as HIstakes) converted from non-responders at a higher rate than those not offered a sweepstakes.
· No statistically significant demographic or attitudinal differences were found for those offered HIstakes entries versus those who were not.
· A single, large cash sweepstakes prize produced higher response and completion rates among confirmed opt-in Harris Poll Online members than did other non-monetary prize packages and smaller grand prize amounts combined with numerous smaller cash prizes.
· Respondents who are offered HIpoints are more likely to finish surveys that they start than those who are not.
· There is an interaction effect between the information about the sender provided in the “from” line and the information in the subject line of the invitation.
· HTML survey invitations have no statistically significant effects on survey participation rates relative to text survey invitations.