The Pearson Correlation documents that the scores are in the same relative order over time and the paired t-test determines if there is a shift in means. A more direct approach is to use a generalizability analysis where the relative error ICC is the reliability ignoring mean differences and the absolute plus relative error ICC takes into account both.
Brennan, R.L. (1983). Elements of generalizability theory. Iowa City, IA: ACT Publications. Cronbach, L.J., Gleser, G.C., Nanda, H., & Rajaratnam, N. (1972). The dependability of behavioral measurement: Theory of generalizability for scores and profiles. New York: John Wiley & Sons, Inc. (Cronbach, Gleser, Nanda, & Rajaratnam, 1972). Paul R. Swank, Ph.D. Professor, Developmental Pediatrics Medical School UT Health Science Center at Houston -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Richard Hoenes Sent: Monday, May 10, 2004 1:52 PM To: [EMAIL PROTECTED] Subject: [edstat] paired t-test for test-retest reliability reference? I submitted a paper that used a Pearson correlation and a paired t-test to estimate test-retest reliability. The journal has a new statistician who first had me remove that Pearson correlation as unnecessary and who now wants a reference for using a paired t-test as a measure of test-retest reliability. Of course, I can find other papers that use a paired t-test for a test-retest measure but I cannot find an actual reference that says it is valid. Any help would be appreciated. . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . ================================================================= . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
