How does the market use citation data?

"A large literature following Hirsch (2005) has proposed citation-based indexes that could be used to rank academics. This paper examines how well several such indexes match labor market outcomes using data on the citation records of young tenured economists at 25 U.S. departments. Variants of Hirsch's index that emphasize smaller numbers of highly-cited papers perform better than Hirsch's original index and have substantial power to explain which economists are tenured at which departments. Adjustment factors for differences across fields and years of experience are presented"--National Bureau of Economic Research web site.