Same-store Sales: Also referred to as “comps,” a statistic used in retail industry analysis. Same-store sales measure percentage changes in revenue for retailers’ stores that have been open for more than a year. This statistic allows investors to determine what portion of new sales has come from sales growth and what portion from the opening of new stores. This analysis is import because, although new stores are good, a saturation point – where future sales growth is determined by same store sales growth – eventually occurs.

Source: Investopedia, Fool.com