Value-of-information analysis of testing strategies: estimating the effect of uncertainty about the proportion of chemicals that are true human carcinogens.

Choosing a cost-effective strategy for classifying chemicals as human carcinogens and non-carcinogens depends upon the costs of false positives (carcinogens erroneously treated as non-carcinogenic) and false negatives (non-carcinogens erroneously treated as carcinogenic); upon the accuracy (sensitivity and specificity) of the classification strategy; and upon the underlying proportion of carcinogens in the population of chemicals to be classified. If these values are known, value-of-information analyses can indicate the most cost-effective among three strategies: classify as carcinogenic without testing, classify as non-carcinogenic without testing, or choose the most cost-effective test and classify on the basis of the test result. When some or all of the values are uncertain, the analysis becomes more complex, but still helps to guide decisions among the three classification strategies.