A systematic consistency analysis and optimization procedure is applied to models of representative ozone, OH, and HO2 observations in the mesosphere and upper stratosphere. The approach considers both measurement and rate parameter uncertainties. The results show some data point inconsistencies and the inability of the accepted photochemical mechanism to predict observations without unfavored large alterations of many rate constants from their consensus values. Optimization results do favor larger rate constants for OH + O and photolytic ozone and OH production.