PhD/PsyD Reliable Change Index question

[erg923]

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Is there a reliable change index for common measures such as PCL-M, PHQ-9, GAD-7? We use these as follow-up and outcome measures and nobody on my team can answer this for me.

 

[WisNeuro]

You can calculate these if you have the numbers. In the validation studies, just pull the test-retest reliability and plug it into the RCI equation. You could also consider clinically significant change.

http://www.personal.kent.edu/~dfresco/CRM_Readings/JCCP_Jacobson_ClinSIG.pdf

 

[erg923]

You can calculate these if you have the numbers. In the validation studies, just pull the test-retest reliability and plug it into the RCI equation. You could also consider clinically significant change.

http://www.personal.kent.edu/~dfresco/CRM_Readings/JCCP_Jacobson_ClinSIG.pdf

Thanks. I suppose that what I was getting at, but i didnt think you could figure CS change if you didnt know the RCI?

 

[WisNeuro]

True, I do think you need the RCI, but you can calculate that if you have the test-retest reliability. You may have to dig and find the validation studies for said instruments, but they shouldn't be too hard to find.

 

[WisNeuro]

If you just want a general guideline, the National Center for PTSD says

"Good clinical care requires that clinicians monitor patient progress. Evidence for the PCL for DSM-IV suggests that a 5-10 point change represents reliable change (i.e., change not due to chance) and a 10-20 point change represents clinically significant change. Therefore, it was recommended to use 5 points as a minimum threshold for determining whether an individual has responded to treatment and 10 points as a minimum threshold for determining whether the improvement is clinically meaningful using the PCL for DSM-IV."

 

[AcronymAllergy]

Like WisNeuro mentioned, if you have test-retest data available (e.g., the test-retest correlation coefficient, sample size, and test-retest score means and standard deviations), you can essentially calculate this for any measure you want. You can also decide if you want to use a "standard" RCI equation (e.g., Chelune et al. developed one that built on previous work and incorporated practice effects) or regression-based reliable change formulae (I think it's Crawford who's done a lot of work in this area). You can then use this info to determine how likely it is that a change of +/- XX will occur. If Crawford is the right name, you could google him, as I believe he posts a bunch of his reliable change work on his website.

It can of course get a bit hairy if you're using test-retest data from an interval that's substantially different from the one you're examining (e.g., test-retest data is from a period of 1 month, but you're looking at 1-2 years), but hey, it's still likely better than nothing.