Waddock and Graves (1999)

Waddock, Sandra A., and Samuel B. Graves. "Assessing the Link Between Corporate Governance and Social/Financial Performance." International Association for Business and Society: 1999 Proceedings. 

Compares Business Week's ratings of 87 company boards of directors (data from 1996 and 1997) with social ratings from Kinder, Lydenberg, Domini & Co.'s SOCRATES database. Finds strong differences between 'good board' and 'bad board' companies, particularly in the 1997 data set. Companies with highly-rated boards scored significantly higher on KLD's metrics for Employee Relations (p<0.01 for 1997, p<0.10 for 1996) and Diversity (p<0.01 for 1997, p<0.10 for 1996). Finds the most pronounced differences among financial variables - Return on Equity, Return on Assets, Return on Sales, and 10-year return were all highly significant (p<0.001 for both time periods) - suggesting the possibility that industry effects, which the authors do not control for, may be at work.