ABSTRACT
It is well worth while checking to see whether one’s high hopes from a technique were justified by events. We went to the trouble of jotting down the results we expected from using NPV, for example. What actually happened? From such a postmortem one can sometimes learn from past mistakes. Considerable practical difficulties stand in the way of an accurate assessment of this type: for example, if Method Study is introduced into a factory where, quite by chance, a new process is being introduced at the same time, it is not always easy to decide how much of the reduction in the labour force is due to each factor.
