Barcode scanners were introduced in the 1970s as a way to reduce labor costs in stores, particularly at checkout. This paper is the first to estimate their effect on productivity. I use store-level data from the 1972, 1977, and 1982 Census of Retail Trade, matched to data on store scanner installations, to estimate scan- ners’ effect on labor productivity. I find that early scanners increased a store’s labor productivity, on average, by approximately 4.5 percent in the first few years, mostly due to a 15–17 percent increase in cashier productivity. Setup costs significantly offset the short-run productivity effect.
That is from a paper by Emek Basker published in the new number of The Journal of Applied Economics. A graph from the paper:
The draft of the paper is here.