Progress on the CSE diagnostic study. Application of McNemar's test revisited.

The authors describe an extension of McNemar's test that can be used to compare diagnostic performance when multiple statements are obtained from computer analysis or visual interpretation of the ECG. If two or more diagnostic statements are made, by definition only one can be correct for the cases in the CSE pilot database, which were selected for single, clinically well documented, abnormalities. If one statement stood out from others as being made with the highest degree of certainty, that was accepted as the single interpretation, right or wrong. However, when two or more statements were made with the same degree of certainty and only one statement was correct, then in the previous application of McNemar's test that interpretation was given credit for being correct. In the extension of the method presented in this article, such an interpretation is given partial credit for the one correct statement and partial discredit for any incorrect statement, thereby reporting the results more properly in the sensitivity and specificity statistics for the different diagnostic categories.