For quite some time long-only index funds have been suspected of being responsible for price increases in agricultural futures markets. This suspicion has prompted demands to drastically limit long-only index funds' scope of activity. Such demands and their underlying diagnoses, however,...

This paper investigates four topics. (1) It examines the different roles played by the propensity score (probabilitiy of selection) in matching, instrumental variable and control functions methods. (2) It contrasts the roles of exclusion restrictions in matching and selection models. (3) It...

This paper summarizes our recent research on evaluating the distributional consequences of social programs. This research advances the economic policy evaluation literature beyond estimating assorted mean impacts to estimate distributions of outcomes generated by different policies and determine...