Store performance measures include both quantitative measures (like revenue, profits, and conversion rate) as well as qualitative ones (like the level of service provided in the stores). Quantitative measures like sales, expenses, and profits are usually available from financial data. While information on store sales can be obtained from POS data, labor expenses are gathered from wage-payroll data, usually at the monthly level. In order to ascertain other expenses like inventory shrink, administrative expenses etc. it is necessary to have access to stores' financial (P&L) statements. These financial measures can be used to construct additional measures like labor productivity (e.g. sales per labor hour) and level of employee turnover. If traffic data are also available, then additional store performance mea- sures like conversion rate (defined as the ratio of number of transactions to traffic), basket value (ratio of sales volume to number of transactions), and traffic to associate ratio (ratio of number of customers to number of sales associates) can be calculated. Qualitative measures on service quality are obtained from customer surveys.

The two most common challenges encountered in conducting empirical research on retail labor are data availability and dealing with endogeneity issues between labor and store performance. As