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To examine the effects of lotteries on response behavior, five experiments were conducted in a nonprofit online panel. The type of lottery offered for study participation was a cash lottery, a voucher lottery, or a lottery of surprise gifts of either known or unknown value. The control group was not offered a lottery. Dependent measures were response, retention, and several facets of response quality. None of the lotteries significantly increased response, retention, or response quality. However, looking at effect sizes reveals a pattern across the five experiments that can inform and refine the practice of employing lotteries in nonprofit online panels. This pattern suggests that lotteries are more effective with panelists low in motivation than high in motivation. [ABSTRACT FROM AUTHOR]

Two incentive experiments on response behavior were conducted in a nonprofit online panel. Experiment 1 examined effects of a lottery and of the lottery’s splitting into multiple prizes. Two cash lotteries and a no-incentive control group were compared. One lottery was announced to be paid out in one lump sum, whereas the other lottery was split into multiple smaller prizes. Dependent variables were two facets of response quantity, namely response and retention, and two facets of response quality, namely nondifferentiation and item nonresponse. Moreover, panelists’ characteristics were tested whether they moderated the lottery effects. The lottery and its splitting did not significantly affect response behavior; however, in terms of effect sizes, splitting the lottery mildly decreased response quantity. Experiment 2 was in part aimed at replication. In addition, it examined the effect of offering study results. Dependent variables were response, retention, and nondifferentiation. The cash lottery mildly enhanced response quantity and quality, whereas splitting the lottery tended to decrease response quantity. Offering study results had no impact on response behavior, both as a stand-alone incentive and in combination with a lottery. The two experiments revealed moderating effects, but these were not stable across both studies. A share of invitees in Experiment 1 was reinvited in Experiment 2, thus enabling analysis of whether their lottery condition in Experiment 1 influenced their response behavior 5 months later in Experiment 2. No such longitudinal effects were found. [ABSTRACT FROM PUBLISHER]

A longitudinal experiment examined the influence of a lottery of gift certificates on response and retention in a four-wave study conducted in an online panel. Independent of the lottery, people who responded in a given wave were more likely to respond in the next wave. This process was characterized to follow a first-order Markov chain. There was a direct positive effect of the lottery on response only at the first wave of the study. However, mediated by the Markov process, the positive effect of the lottery on response at the first wave was carried over into later waves. The lottery did not have any effect on retention. Furthermore, it was found that retention at a given wave is a reliable predictor for response at the next wave. This information could be used by survey managers to diagnose and act on any impending nonresponse. [ABSTRACT FROM AUTHOR]

Six incentive experiments were conducted in a nonprofit online panel. In each experiment, the incentive offered for participation was a cash lottery. The control group was not offered any incentive. The cash lottery was offered in two versions: Either the total payout of the lottery was mentioned, or the lottery was split into multiple prizes. Dependent measures included response and retention rates. The results of the six individual experiments were meta-analytically summarized. Cash lotteries relative to no incentives did not reliably increase response or retention; neither did it make a significant difference if one large prize or multiple smaller prizes were raffled. [ABSTRACT FROM AUTHOR]