Total Productivity Measurement in Bus Transit: Comment

Abstract

This technical note comments on a 1990 paper by Sumanth and Adya that appeared in this journal. In that paper the authors determined total productivity and showed how innovations occurring in transit systems they analyzed have affected it. Using the definition of the authors, it is shown that there is a misspecification problem in the equations used by Sumanth and Adya in determining the effect of automation on total productivity. A relationship between total productivity and input productivity is formally derived, and it is suggested that this relationship is better than the one the authors presented.