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Comparison of predictive values of two diagnostic tests from the same sample of subjects using weighted least squares
Author(s) -
Wang Wenquan,
Davis Charles S.,
Soong SengJaw
Publication year - 2005
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.2332
Subject(s) - wald test , statistics , mathematics , categorical variable , generalized estimating equation , statistic , ordinary least squares , logarithm , score test , sample size determination , likelihood ratio test , statistical hypothesis testing , mathematical analysis
Screening and diagnostic tests are important in disease prevention or control. The predictive values of positive and negative (PPV and NPV) test results are two of four operational characteristics of a screening test. We review an existing method based on the generalized estimating equation (GEE) methodology for comparing predictive values from the same sample of subjects and propose two Wald test statistics derived from the weighted least squares (WLS) method for the analysis of categorical data. Using these results, we propose sample size calculation formulae for this problem. Simulation studies are conducted to compare the performances of the two Wald test statistics (one based on the difference of two PPVs or NPVs, another based on the logarithm of the ratio of two PPVs or NPVs) and the score/Wald test statistic derived from GEE. We recommend using the difference‐based WLS approach. Copyright © 2005 John Wiley & Sons, Ltd.