An analysis of the effect of pre-incentives and post-incentives based on draws on response to web surveys

Most analyses of the effect of incentives on response rates have attempted to extrapolate to the Internet the already existing broad knowledge base of methodologies for personal surveys by telephone and post. However, such knowledge about existing methods is not directly applicable to the Internet-based interviews. This study therefore examines the manner in which different combinations of incentives can affect response to a survey over the Internet. With such a purpose incentives have been chosen based on draws that has been administered under the pre-incentives philosophy (giving the possibility to participate in a draw, independently that the questionnaire was stuffed or not) or post-incentives (giving the possibility to participate in a draw only those that stuffed the questionnaire). A surprising result is that the joint use of pre-incentives and post-incentives slightly improves response rates, although it also causes rates to be considerably lower than when these incentives are used separately.