This document summarizes William Labov's 1962 study of social stratification through the use of (r) in New York City department stores. Labov hypothesized that the differential use of (r) directly corresponds to social ranking. He studied three department stores of differing prestige levels and found that employees and customers at the highest ranking store, Saks Fifth Avenue, had the highest rate of (r) usage, while the lowest ranking store, S. Klein, had the lowest rate. Labov accounted for other variables like age, occupation, race and found patterns of social stratification in (r) usage. The study demonstrated the value of sociolinguistic observation for understanding social differentiation.