How to calculate Reliable Change Index using SPSS?


New Member


If I have a sample of 137 individuals with three assessment results (first, 1YR follow-up and 2-Yr follow-up), I am assuming there is a way to calculate this for the group based on differences in two results for each individual (e.g., First to 1 YR score, First to 2 YR score).

Then the formula is Post-test result minus pre-test result divided by the Standard Error of the difference.

For significance, I assume I would use the threshold of t>=1.96 or t<=-1.96 for significance?

Also, I'm wondering how to do this in SPSS, but I will also ask in that forum.