Establishment of a Reliable Change Index for the GAD-7

Thomas Bischoff, Shayne R. Anderson, Joy Heafner, Rachel Tambling

Abstract


Aim: It is increasingly important for mental healthcare providers and researchers to reliably assess client change, particularly with common presenting problems such as anxiety. The current study addresses this need by establishing a Reliable Change Index of 6 points for the GAD-7. Method: Sample size included 116 online community participants using Amazon’s Mechanical Turk (MTurk) and archival data for 332 clinical participants. Participants completed measures of the GAD-7 and the MDI in 2 rounds. Using previously established cutoff scores and Jacobson and Truax’s (1991) method, we establish a Reliable Change Index which, when applied to 2 administrations of the GAD-7, indicates if a client has experienced meaningful change. Results: For the GAD-7, the mean score for the clinical sample was 10.57. For the community sample at Time 1, the mean score was 4.14. A Pearson’s correlation was computed to assess the 14-28-day test-retest reliability of the GAD-7, r(110) = .87, indicating good test-retest reliability. Conclusion: Using the RCI equation, this resulted in an RCI of 5.59. For practical use the RCI would be rounded to 6.

Keywords


reliable change index; clinical significance; clinically meaningful change; anxiety; GAD-7