Stata Programs: Roc Analysis
1. 95% Confidence Intervals For Sensitivity, Specificity, and Likelihood Ratios
dtestci.do contains two programs related to deriving 95% CI for sensitivity, specificity, LR+, and LR-
for a dichotomous test. The first, sespci_i is an immediate form program that calculates sensitivity,
specificity, the 2 LR, and 95% CI for each. The second, sespcidoc, provides brief documentation for
the program. (Revised 1/17/07)
2. ROC ANALYSIS
nrocarea.do contains two programs related to ROC curves. The first, rocintercept, estimates the optimal
sensitivity and specificity (tangency of OOS and ROC curve) and the intercept of the tangent line. The second,
testchar, calculates sensitivities, specificities, and stratum-specific likelihood ratios (plus confidence
intervals) for the operating points that define the convex hull of the ROC curve. nrocarea also has 3 utility
programs used to cumulate test results (cumval), calculate 95% CI for single proportions (pro95ci), and
calculate 95% CI for SSLR (lrci). Finally, there is a utility program, nrocdoc, that provides brief
documentation for the program. bsrocarea2.do provides a program for bootstrapping the optimal sensitivity and specificity; as well as
the intercept of the tangent line. Bootstrapping the intercept yields a standard error, which allows
statistical comparison of the intercepts from competing tests sslrprog.do provides a program (sslr) for estimating stratum-specific likelihood ratios and their 95% CI
for a test characterized by between 2 and 50 ordered categorical outcomes. It also provides a program, sslrdoc,
that provides brief documentation for the program
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