IMPACT OF LOTTERY INCENTIVE ON RESPONSE RATE AND DATA QUALITY: EVIDENCE FROM ORGANIC FOOD CONSUMPTION SURVEY OF CONVENTIONAL SHOPPERS

Incentives of different forms and at different stages are used for motivating people to participate in human subject research. Although it is widely accepted that incentives, in general, play a positive role in increasing participation rate and are widely used, there are exceptions that they may not increase response rate and may even contaminate the quality of data resulting in poor research findings. This study examines the impact of pre- and post-disclosed committed lottery incentives on response rate and data quality in a face-to-face survey of conventional consumers for organic food consumption. A survey was conducted at the premises of four conventional grocery stores in Edmonton, Alberta, Canada. Half of the randomly approached and agreed upon respondents were disclosed the lottery incentives at the beginning, and the rest half were told at the end. Data quality was measured using three indicators – edit occurrences, imputation occurrences, and proportion of incomplete answers. Our study finds little difference in response rate between pre- and post-disclosed committed lottery payments. However, the useability of incomplete questionnaires among post-disclosed lottery was significantly higher than those of pre-disclosed. Our study also shows that people with likings of organic food and buying organic food more frequently are likely to offer a better quality of information.