Excess days lost as an index for identifying jobs with ergonomic stress

A new health impact index, excess cost, is advocated for identifying jobs in need of further study regarding ergonomic problems. The excess cost index is compared with incidence rate, excess count, and severity rate indices in terms of concept and appropriateness to the purpose. The four indices are illustrated with data regarding medical leave from an automobile assembly plant and evaluated in terms of ability to identify jobs most strongly contributing to excessive days lost.