We examine daily prices of eight goods at seventeen retail stores collected in Ann Arbor, Michigan, over a four-month period from November 1 to February 28. We focus on weekly and seasonal price patterns, and on the frequency of price markdowns or “sales.” There were frequent markdowns in the intensive shopping period prior to Christmas, and a tendency for such sales to occur on weekends. We interpret these findings as evidence that a significant number of markdowns are timed to occur when shopping intensity is exogenously high. We complement the imperfect information-based motives for sales in the literature by contributing an additional element based on the role of bulk shopping and increasing returns in the shopping technology.

We examine the reduced-form relationship between per capita income and various environmental indicators. Our study covers four types of indicators: urban air pollution, the state of the oxygen regime in river basins, fecal contamination of river basins, and contamination of river basins by heavy metals. We find no evidence that environmental quality deteriorates steadily with economic growth. Rather, for most indicators, economic growth brings an initial phase of deterioration followed by a subsequent phase of improvement. The turning points for the different pollutants vary, but in most cases they come before a country reaches a per capita income of $8000.