Analyzing Therapeutic Change Using Modified Brinley Plots: History, Construction, and Interpretation

Area of Science:

• Psychology
• Clinical Psychology
• Therapy Outcome Research

Background:

• Brinley plots, used since 1965 for group mean data, were occasionally adapted for individual data between 1979-1995.
• Modified Brinley plots offer a visual method for analyzing individual participant changes in therapy outcome research.

Purpose of the Study:

• To review the history, construction, and interpretation of modified Brinley plots.
• To highlight their utility in therapy outcome research for assessing individual and group changes.

Main Methods:

• The paper reviews the methodology of constructing and interpreting modified Brinley plots.
• Key elements include using orthogonal axes with identical scales and origins to plot individual scores over time.

Main Results:

• Modified Brinley plots effectively display individual change, improvement/deterioration magnitude, outliers, and replication across cases.
• Interpretation is enhanced by integrating reliable change boundaries, clinical cutoffs, means, variances, confidence intervals, and effect sizes.

Conclusions:

• Modified Brinley plots provide direct insights into individual therapeutic change within a group context.
• They are valuable for assessing outcome replication, clinical significance, and complementing other analytical methods in therapy research.