Tools

Reliable Change Index (RCI) Link to heading

The Reliable Change Index (RCI) is a statistical method used to determine whether the change in a patient’s score on a psychological measure over time is statistically significant and not due to measurement error. It helps to distinguish meaningful clinical improvement from random fluctuations or measurement noise.

RCI is calculated by comparing the difference between pre-treatment and post-treatment scores against the standard error of the difference. If the observed change exceeds a critical threshold (usually ±1.96 times the standard error), it is considered a reliable change.

This approach is valuable in psychotherapy research to assess whether individual patients experience real and clinically significant progress, rather than just statistical group effects.

Jacobson, N. S., & Truax, P. (1991). Clinical significance: A statistical approach to defining meaningful change in psychotherapy research. Journal of Consulting and Clinical Psychology, 59(1), 12–19.DOI: https://doi.org/10.1037/0022-006X.59.1.12

Here you can find an online version developed by me.