Damage control productivity: Why econometrics matters

For nonexperimental data, asymmetric specifications of the role of damage control inputs impose restrictions of homotheticity or nonjointness on the underlying technology. A generalized symmetric form where damage control inputs affect factor diminution functions motivates use of symmetric specifications. Panel data and estimation methods are presented to produce robust estimates of damage control productivity that are free of heterogeneity bias. Estimates of the productivity of pesticides for French cereal farm production illustrate that fixed firm and time effects are important. Estimates indicate substantially smaller marginal productivity of pesticides than reported by past studies.