Researchers and clinicians using Jacobson and Truax's index to
assess the reliability of change in patients, or its counterpart by
Chelune et al., which takes practice effects into account, are confused
by the different ways of calculating the standard error encountered in
the literature (see the discussion started in this journal by
Hinton-Bayre). This article compares the characteristics of (1) the
standard error used by Jacobson and Truax, (2) the standard error of
difference scores used by Temkin et al. and (3) an adaptation of
Jacobson and Truax's approach that accounts for difference between
initial and final variance. It is theoretically demonstrated that the
last variant is preferable, which is corroborated by real data.
(JINS, 2004, 10, 888–893.)