Evidence fit for evidence-based practice: Implications for the curriculum and new ways of looking at data.
Current proposals for methodological reform in psychology call for research to be more idiographic and less dependent on group averaging and null-hypothesis statistical testing. This paper reviews this development in the context of evidence-based practice and considers several major changes in the methodology curriculum required if reform is to occur and if evidence is to be fit for use in evidence-based practice. These changes include the teaching of the new statistics (estimation, confidence intervals, effect sizes, and meta-analysis); visual analysis techniques for the display of individual data in group contexts; replication; single-case research designs; and more sophisticated statistical tools (e.g., P-factor analysis). The presentation will focus on the construction and interpretation of modified Brinley plots, a technique for analysing change over time that is particularly suitable for idiographic analysis of outcome research in behavioural and cognitive-behavioral therapies. Modified Brinley plots are scatter-plots that compare individual scores at time 1 (normally pre-treatment) with scores at various times post-treatment. If the origin and axis scales are the same no or little change is shown by data points clustering on or about the 45o diagonal line. Change associated with treatment (improvement or deterioration) is shown by shifts away from the diagonal. Interpretation is aided by the addition of clinical cut-offs, and indicators of means, variances, confidence intervals, measurement error, reliable change, and effect sizes. Both between-group and within-group data may be presented and analysed with these plots, and they form the basis of new visual displays for group research using single-case research designs.