Derivation of Delays Based on Input-Output Analysis

In a recent paper Michalpoulos and Pisharody (1981) contend that traditional input-output analysis results in substantial overestimation of delays, and they develop an alternate, more laborious, calculation method. This premise is incorrect since input-output analysis is nothing more than a simple accounting method, which by definition gives exact results. It should give results consistent with the more laborious method proposed by those authors.