R Tutorial: Test-retest reliability (using intraclass correlation)

This video will show you how to conduct test-retest reliability analysis using an intraclass correlation as well as a Bland-Altman plot. Data and code can be found here drive.google.c...

[@adoi]

Hi, thanks for the video.
May I ask what the difference between psych::testRetest and psych::ICC is? I understand for psych::testRetest, it actually takes all items and compares them between the first and second time point. From what I see in psych::ICC, it seems to be taking 1 value only. Is the 1 value a total score?

[@brazilfootball]

Nice video! Short and sweet. Does this also test the strength of association (effect size) between a continuous and nominal (categorical) variable?

[@hebametwalli207]

hello, thank you for the explannation. Can i conduct the ICC with the by function. For example, seeing whether the ICC differs between 2 groups. Can you please provide the syntax for that?. Thanks again.

[@jorgemmmmteixeira]

can we do the same with 3 time points? ty