Connections appear to be helpful in many contexts such as obtaining a job, a
promotion, a grant, a loan or publishing a paper. This may be due to favoritism
or to information conveyed by connections. Attempts at identifying both effects
have relied on measures of true quality, generally built from data collected
long after promotion. This empirical strategy faces important limitations.
Building on earlier work on discrimination, we propose a new method to identify
favors and information from classical data collected at time of promotion.
Under natural assumptions, we show that promotion decisions look more random
for connected candidates, due to the information channel. We obtain new
identification results and show how probit models with heteroscedasticity can
be used to estimate the strength of the two effects. We apply our method to the
data on academic promotions in Spain studied in Zinovyeva & Bagues (2015). We
find evidence of both favors and information effects at work. Empirical results
are consistent with evidence obtained from quality measures collected five
years after promotion.Comment: 35 pages, 2 figures, 13 table