In diagnostic medicine, the test that determines the true disease status without an error is referred to as the gold standard. Even when a gold standard exists, it is extremely difficult to verify each patient due to the issues of cost effectiveness and invasive nature of the procedures. In practice some of the patients with test results are not selected for verification of the disease status which results in verification bias for diagnostic tests. The ability of the diagnostic test to correctly identify the patients with and without the disease can be evaluated by measures such as sensitivity, specificity and predictive values. However, these measures can give biased estimates if we only consider the patients with test results who also underwent the gold standard procedure.
The emphasis of this paper is to apply the log-linear model approach to compute the maximum likelihood estimates for sensitivity, specificity and predictive values. We also compare the estimates with Zhou’s results and apply this approach to analyze Hepatic Scintigraph data under the assumption of ignorable as well as non-ignorable missing data mechanisms. We demonstrated the efficiency of the estimators by using simulation studies.
“Correction of Verication Bias using Log-linear Models for a Single Binaryscale Diagnostic Tests,” was published in the Journal of Biometrics & Biostatistics.
Dr. Haresh Rochani, assistant professor of biostatistics at Georgia Southern University Jiann-Ping Hsu College of Public Health was the lead author. Dr. Hani Samawi, director of the K.E. Peace center for biostatistics, Dr. Robert Vogel, dual department chair for biostatistics and epidemiology, and Dr. Jingjing Yin, assistant professor of biostatistics at Georgia Southern were co-authors.