Barcodes and barcode scanners transformed the grocery industry in the 1970s. I use store-level data from the 1972, 1977, and 1982 Census of Retail Trade, matched to data on store scanner installations, to estimate scanners' effect on labor productivity. I find that early scanners increased a...

This dissertation consists of three chapters. The first chapter explores the effect of Wal-Mart expansion on local retail employment. The phenomenal expansion of Wal-Mart provides a clean case for studying the labor-market effects of increased efficiency. I estimate the effect of Wal-Mart entry...