Clinical Chemistry, Vol 30, 751-754, Copyright © 1984 by American Association for Clinical Chemistry

A direct comparison of two slope-estimation techniques used in method- comparison studies

CA Parvin

Least-squares regression estimation of the slope and intercept in method-comparison studies is the most common method of data evaluation despite well known theoretical difficulties with this approach. An alternative estimation technique has been suggested, which avoids some of these theoretical difficulties. I developed an exact mathematical relationship between these two slope estimates in order to directly compare their characteristics. A simple approximate formula for the relative difference between the two slope estimates is also derived. Using these mathematical relationships, I compare the two estimation techniques, using data from published method-comparison studies. In most of the published method comparisons the differences between slope estimates were trivial, but in some the differences were large enough to have warranted use of the alternative slope estimate.

The following articles in journals at HighWire Press have cited this article:

				K. Linnet Necessary Sample Size for Method Comparison Studies Based on Regression Analysis Clin. Chem., June 1, 1999; 45(6): 882 - 894. [Abstract] [Full Text] [PDF]

				K. Linnet Performance of Deming regression analysis in case of misspecified analytical error ratio in method comparison studies Clin. Chem., May 1, 1998; 44(5): 1024 - 1031. [Abstract] [Full Text] [PDF]