Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 2 of 2
Full-Text Articles in Entire DC Network
On The Size Accuracy Of Combination Tests, Chris Lloyd
On The Size Accuracy Of Combination Tests, Chris Lloyd
Chris J. Lloyd
One element of the analysis of adaptive clinical trials is combining the evidence from several (often two) stages. When the endpoint is binary, standard single stage tests statistics do not control size well. Yet the combined test might not be valid if the single stage tests are not. The purpose of this paper is to numerically and theoretically examine the extent to which combining basic tests statistics mitigates or magnifies the size violation of the final test.
Multinomial Logistic Regression: An Application To Estimating Performance Of A Multiple Screening Test For Bowel Cancer When Negatives Are Unverified., Chris Lloyd, Don Frommer
Multinomial Logistic Regression: An Application To Estimating Performance Of A Multiple Screening Test For Bowel Cancer When Negatives Are Unverified., Chris Lloyd, Don Frommer
Chris J. Lloyd
This paper describes a method of estimating the performance of a multiple screening test where those who test negative do not have their true disease status determined. The methodology is motivated by a dataset on 49,927 subjects who were given K=6 binary tests for bowel cancer. A complicating factor is that individuals may have polyps present in the bowel, a condition that the screening test is not designed to detect but which may be worth diagnosing. The methodology is based on a multinomial logit model for Pr(S|R_6), the probability distribution of patient status S (healthy, polyps or diseased) conditional on …