High wage workers and high wage peers

This paper investigates the effect of coworker characteristics on wages, measured by the average person effect of coworkers in a wage regression. The effect of interest is identified from within-firm changes in workforce composition, controlling for person effects, firm effects, and sector-specific time trends. My estimates are based on a linked employer employee dataset for the population of workers and firms of the Italian region of Veneto for years 1982-2001. I find that a 0.1 increase in the average labour market value of coworkers' skills (which is around one within-person standard deviation) is associated with a 3.6 percent wage premium. I also find that a sizeable share of the wage variation previously explained by unobserved individual and firm heterogeneity may be due to variation in coworker skills. An event-type study, a Placebo exercise and a series of heterogeneity analyses lend credibility to the baseline results. I also evaluate the role of the spillover effects for wage differentials between specific groups of workers. I find that around 12 percent of the gender wage gap and 10 to 16 percent of the immigrant wage gap can be explained by differences in coworker characteristics.