Obuchowski-Rockette analysis for multi-reader multi-case (MRMC) readers-nested-in-test study designs with unequal numbers of readers or cases

The Obuchowski-Rockette method has been an important tool for analyzing multi-reader multi-case (MRMC) radiologic imaging data. Although the typical study design for such studies has been the factorial design, where each reader reads each case using each test (modality), sometimes a reader-nested-in-test design is more appropriate. We consider such an example in this talk, where 53 Australian and 15 Singaporean breast radiologists interpreted the same test in their respective locations. In this paper we show how the Obuchowski-Rockette method can be used for analysis of such data, without assuming that the number of readers is the same for each test.