Lotteries and study results in market research online panels

An incentives experiment was conducted in a commercial online panel to examine the effects of lotteries and of offering study results on response behaviour as reflected by participation, retention and item non-response. A cash lottery was implemented, with three different payouts that were raffled either in one lump sum or split into multiple smaller prizes. The lottery groups were contrasted to a control group without incentive. Independent of the lottery, half of the participants were offered a report of study results. Participation was higher with a lottery, when raffling the payout in a lump sum and with higher single prize size, whereas item non-response was smaller with high total payouts. Furthermore, offering study results decreased participation.