The sixth stool guaiac test: $47 million that never was.

In a 1975 paper, Neuhauser and Lewicki analysed a colorectal cancer screening policy approved by the American Cancer Society. Their analysis yielded an incremental cost per case detected in excess of $47 million. This vivid demonstration of the impact of marginal analysis is frequently cited by health economists and is often used for pedagogic purposes. The analysis is incorrect because of two fundamental errors. We have reanalysed the protocol in two stages. After correction for these errors, the $47 million disappears, the marginal cost is quite modest and the policy appears to be defensible on economic grounds.