The Cusum Chart: A Supergraph for Personnel Managers

The cusum (cumulative sum) chart is a type of graph which takes a little longer to draw than one of the traditional kind but which gives a lot more information. It is particularly useful for plotting the evolution of processes like recruitment, promotion and wastage because it presents information in a way that enables the eye to separate true trends and changes from a background of random variation. It may be used both for retrospective analysis and for monitoring; in the latter role it can give early warning of changes in (for example) wastage rates. Though the technique is not one which demands masses of data as a prerequisite, it offers its richest rewards in the field of large computer‐based data banks.