Methodological PaperAnalyzing Therapeutic Change Using Modified Brinley Plots: History, Construction, and Interpretation☆
Section snippets
Brinley Plots: A Short History
The history begins with a type of scatter plot developed by Brinley (1965), who measured the performance speed of young and elderly participants in several different cognitive tasks and calculated the group mean speed for each task separately for younger (My) and older (Mo) participants. He then plotted points representing each My (x-axis) and same-task Mo (y-axis) pair. With the origin and scales of the scatter plot axes the same, if there were no systematic performance differences between
Creation and Interpretation of Modified Brinley Plots
Therapy outcome research typically involves participants sharing a common problem who are repeatedly observed (up to z times), normally at t1 before therapy and then again later (t2–Z; t2 hereafter, for simplicity). Many protocol variations are possible, with participants divided into control as well as therapy groups and with repeated measures for all participants in baseline and during and after intervention, and measurement of multiple dependent variables (DVs). The net result is a matrix of
Displaying Means, CIs, and ESs
To this point the paper has shown how modified Brinley plots permit the informative display of each individual’s data and the immediate perception of their reliable and clinically significant change. It next discusses how nomothetic information can be overlaid on the plot, focusing in particular on means, CIs, and various ES measures.
Between-Group Comparisons
So far the focus has been on examining within-participant change over time. Typical therapy outcome studies, however, often combine within- and between-participant conditions, commonly having both therapy and control/comparison groups. Modified Brinley plots are first and foremost a within-subject data analysis tool, but that does not prevent them from being used to compare change over time in different groups. In Jacobson et al. (1984) and Sobell et al. (1995), data from different therapy
Utility and Limitations of Modified Brinley Plots
In contrast to conventional graphs reporting group data, modified Brinley plots primarily display individuals’ data and are, therefore, idiographic—they drill down from the group aggregate level to display patterns of individual response to therapy (Sobell et al., 1995). They do not, however, necessarily identify who each data point represents, and this is a limitation in the extent to which they are fully idiographic. Can these plots be made even more idiographic, perhaps by displaying
Conclusion
Cohen (1990) reflected that, in changing psychology’s methodological practices, “Things take time” (p. 1311). Even so, Stunkard and Penick’s (1979) inaugural modified Brinley plot did not deserve to suffer more than three decades of obscurity and neglect, despite attempts by Jacobson et al. (1984) and Sobell and colleagues (1995) to revive interest. Neither has their concern that nomothetic research does not deliver information directly useful to clinicians gone away in the meantime. Recently,
Conflict of Interest Statement
The author declares no conflicts of interest in the production of this paper.
References (89)
- et al.
Utilizing reliable and clinically significant change criteria to assess for the development of depression during smoking cessation treatment: The importance of tracking idiographic change
Addictive Behaviors
(2011) - et al.
A method of assessing change in a single-subject: An alteration of the RC Index
Behavior Therapy
(1986) - et al.
Psychotherapy outcome research: Methods for reporting variability and evaluating clinical significance
Behavior Therapy
(1984) - et al.
Combining nonoverlap and trend for single-case research: Tau-U
Behavior Therapy
(2011) - et al.
Micronutrients reduce stress and anxiety following a 7.1 earthquake in adults with attention-deficit/hyperactivity disorder
Psychiatry Research
(2011) - et al.
Portraying alcohol treatment outcomes: Different yardsticks of success
Behavior Therapy
(1995) Publication manual
(2010)- et al.
Assessing clinical significance: Does it matter which method we use?
Journal of Consulting and Clinical Psychology
(2005) - et al.
Research methods in clinical psychology
(2016) - et al.
The scientist-practitioner: Research and accountability in educational settings
(1984)
Why can’t we be more idiographic in our research?
Perspectives on Psychological Science
Changing frontiers in the science of psychotherapy
Single-case research adaptations for the analysis of group data
Single-case research designs and the scientist-practitioner ideal in applied psychology
Adapting single-case research designs for research with groups
The test-retest reliability and responsiveness to change of the Hand Function Survey during stroke rehabilitation
Australian Occupational Therapy Journal
Time-series statistical analysis of single case data
Visual analysis in single-case research
Cognitive sets, speed and accuracy of performance in the elderly
Readings in information visualization: Using vision to think
Graphs in scientific publications
American Statistician
Visualizing data
Things I have learned so far
American Psychologist
The earth is round (p < .05)
American Psychologist
Applied behavior analysis
Understanding the new statistics: Effect sizes, confidence intervals, and meta-analysis
The new statistics: Why and how
Psychological Science
Twelve frequently asked questions about growth curve modelling
Journal of Cognition and Development
Misuse of statistical tests in three decades of psychotherapy research
Journal of Consulting and Clinical Psychology
Augmenting visual analysis in single-case research with hierarchical linear modelling
Behavior Modification
Increasing speed of processing with action video games
Current Directions in Psychological Science
Now you see it: Simple visualization techniques for quantitative analysis
Toward improved statistical reporting in the Journal of Consulting and Clinical Psychology
Journal of Consulting and Clinical Psychology
Visual aids and structured criteria for improving visual inspection and interpretation of single-case designs
Journal of Applied Behavior Analysis
Effect size estimates: Current use, calculations and interpretations
Journal of Experimental Psychology: General
Historical development of the graphical representation of statistical data
Osiris
Surrogate science: The idol of a universal method for scientific inference
Journal of Management
Clinically significant symptom reduction in children with attention-deficit/hyperactivity disorder treated with micronutrients: An open label reversal design study
Journal of Child and Adolescent Psychopharmacology
Improving the relationship between the randomized clinical trial and real-world clinical practice
Psychotherapy
The idiographic application of nomothetic empirically based treatments
Clinical Psychology: Science and Practice
Alphabet soup: Blurring the distinctions between p’s and α’s in psychological research
Theory and Psychology
Why p values are not a useful measure of evidence in statistical significance testing
Theory and Psychology
Statistics for assessing the clinical significance of psychotherapy techniques: Issues, problems, and new developments
Behavioral Assessment
Clinical significance: A statistical approach to defining meaningful change in psychotherapy research
Journal of Consulting and Clinical Psychology
Cited by (36)
Reliable change and the reliable change index: still useful after all these years?
2022, Cognitive Behaviour TherapistThe Lighter Touch: Less-Restriction in Sequentially Implemented Behavioral Sleep Interventions for Children with Rare Genetic Neurodevelopmental Conditions
2024, Journal of Autism and Developmental DisordersDaily socket comfort in transtibial amputee with a vacuum-assisted suspension system: study protocol of a randomized, multicenter, double-blind multiple N-of-1 trial
2023, BMC Sports Science, Medicine and RehabilitationLess Restrictive Behavioral Interventions for Sleep Problems in Children with Neurodevelopmental Disorders: A Single Case Feasibility Study
2023, Journal of Developmental and Physical Disabilities
- ☆
I gratefully acknowledge Heather Duncan, Brian Haig, Joanna Lothian, Jess McIvor, Cathy Robson, Julia Rucklidge, and Ellen Sole for their help in the preparation of this paper.