There are two popular statistical approaches to biomarker evaluation. One models the risk of disease (or disease outcome) using, for example, logistic regression. A marker is useful if it has a strong effect on risk. The second evaluates classification performance using the ROC curve. There is controversy about which approach is most appropriate. Moreover, the two approaches often give contradictory results on the same data. A marker that has a strong effect on risk may not improve the ROC.
We present a new graphic, the predictiveness curve, that complements the risk modeling approach. It assesses the usefulness of a risk model when applied to the population. In addition, the predictiveness curve relates directly to classification performance measures. We show that it provides a more coherent and cohesive assessment of a risk marker or model than either the risk modeling or ROC approaches alone.
We demonstrate first using data on PSA and risk factors for prostate cancer. We then apply the methods to two datasets on CRP and risk factors, the Framingham Heart Study and the Women?s Health Study.
- Margaret S. Pepe, Ziding Feng, Ying Huang, Gary M. Longton, Ross Prentice, Ian M. Thompson, and Yingye Zheng, "Integrating the Predictiveness of a Marker with its Performance as a Classifier" (June 1, 2006). UW Biostatistics Working Paper Series, #289 . http://www.bepress.com/uwbiostat/paper289
- Ying Huag, Margaret S. Pepe, and Ziding Feng, "Evaluating the Predictiveness of a Continuous Marker" (March 1, 2006). UW Biostatistics Working Paper Series, #282. http://www.bepress.com/uwbiostat/paper282
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