Comps, or Comparable Store Sales, are a key metric used by retailers to measure the performance of a single store against similar stores in terms of sales and profitability. Comps provide retailers with an apples-to-apples comparison of sales and profitability over time, thus allowing them to compare stores to identify opportunities for improvement.

Comps are typically measured over a period of time or a point in time, such as month-over-month, quarter-over-quarter, or year-over-year. The results are then expressed as a percentage change in sales and profitability.

In order to ensure accuracy and reliability, comps should be done on similar stores that share the same customer base and selling environment. Doing comps on stores that are geographically disparate can skew the results due to the different factors present in the local area. Additionally, not including new stores in comps removes extraneous factors, such as grand opening promotions, that may skew results.

Retailers use comps to determine which stores are most profitable and and why. They may identify stores that consistently outperform others, and then analyze the characteristics that make them successful. For example, by comparing the marketing activities, product mix, customer service, and other factors, a retailer can uncover the keys to success for a store and then apply them to other stores.

Comps can also be used to identify potential opportunities for growth. By comparing like stores, a retailer can gain insight into market segments and trends that can inform initiatives, such as product launches and marketing campaigns.

Overall, comps are an important tool for retailers to measure the performance of a single store against its peers. By analyzing the results of comps, retailers can identify successes and opportunities for improvement, and inform their decision-making processes.