Evaluating Data Quality in Reports of Sales in a Retail Establishment Survey

This paper examines failure to use records in sales reporting across about 12,000 store owners participating in a retail measurement panel in a Southeast Asian country. Reported sales based on the storekeeper's memory (oral reports) were lower than those from records, as expected. More surprisingly, oral reports acted as a supplement to record-based reports at the same store, such that stores that had oral reports had higher total sales than those with invoices. Although stores were expected to either have or not have a reliable record system, many stores used both. Findings varied over individual categories of products. Little research has examined the quality of reports of retail (consumer) sales from store owners in non-western countries. The paper suggests that improving data collection tools, rather than a single statistical adjustment approach, may be a more fruitful avenue for reducing measurement error in sales reports.