Comparison of student's t-test and the Dorfman-Berbaum-Metz (DBM) method for the statistical comparison of competing diagnostic modalities

Yulei Jiang

doi:10.1117/12.462679

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12 April 2002 Comparison of student's t-test and the Dorfman-Berbaum-Metz (DBM) method for the statistical comparison of competing diagnostic modalities

Yulei Jiang

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Proceedings Volume 4686, Medical Imaging 2002: Image Perception, Observer Performance, and Technology Assessment; (2002) https://doi.org/10.1117/12.462679
Event: Medical Imaging 2002, 2002, San Diego, California, United States

Abstract

Both student's t-test for paired data and the Dorfman- Berbaum-Metz (DBM) method report a P value in comparing ROC curves of competing diagnostic modalities. We empirically compared the P values from the t-test and the DBM method using data of two observer studies involving the lung-nodule detection (15 readers 240 cases) and breast-lesion classification (10 readers 104 cases). We made 596,637 comparisons based on data drawn from different combinations and subsets of the readers and cases. The average difference in the P values was 0.11 and 0.058 in the lung nodule study (of two separate analyses) and 0.0061 in the breast lesion study. The lung nodule study showed, in the analysis that demonstrated statistical significance with the original full dataset, both P<0.05 or both p>0.05 in 83% of the comparisons. The t-test alone reported P<0.05 in 17%, and the DBM method alone reported P<0.05 in 1% of the comparisons. A second analysis of the part of the lung nodule study that did not show statistical significance with the original full dataset found both P<0.05 or both P>0.05 in 99% of the comparisons. The t-test alone reported P<0.05 in 1%, and the DBM method alone reported P<0.05 in less than 1% of the comparisons. The breast lesion study showed both P<0.05 or both P>0.05 in 91% of the comparisons. The t-test alone reported P<0.05 in 5%, and the DBM method alone reported P<0.05 in 4% of the comparisons. These results indicate that the t-test and the DBM method generally report similar P values, but their conclusions regarding statistical significance often differ and the DBM method should be used because it accounts for both reader and case variances.

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Yulei Jiang "Comparison of student's t-test and the Dorfman-Berbaum-Metz (DBM) method for the statistical comparison of competing diagnostic modalities", Proc. SPIE 4686, Medical Imaging 2002: Image Perception, Observer Performance, and Technology Assessment, (12 April 2002); https://doi.org/10.1117/12.462679

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