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Research methods in clinical psychology: An introduction for students and practitioners Chris Barker, Nancy Pistrang, and Robert Elliott. CHAPTER 12 Analysis, interpretation and dissemination. Overview. Interpretation What is the strength and significance of the findings?
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Research methods in clinical psychology:An introduction for students and practitionersChris Barker, Nancy Pistrang, and Robert Elliott CHAPTER 12 Analysis, interpretation and dissemination
Overview • Interpretation • What is the strength and significance of the findings? • What are their scientific and professional implications? • Dissemination • Making the findings known
Qualitative analysis: overview • Analysis is an inductive process • Many different approaches • vary in depth of interpretation / inference • method should fit research questions and the data • Generic processes / general principles • Within-case and cross-case analysis
Frequently used approaches • Grounded theory • Interpretative phenomenological analysis (IPA) • Discourse analysis • Content analysis
Preliminaries to data analysis • Transcriptions • different conventions • anonymity • “Immersion” in the data
Generic processes in analysis • identifying meaning • categorising • integrating Note: cyclical, not linear
Identifying meaning • identifying and labelling ideas • line-by-line (microanalysis) • meaning units • codes (labels): ‘in vivo’ v. abstract • implicit v. explicit meaning
Categorising • themes or categories • method of ‘constant comparison’ • “saturation”
Integrating • linking themes / categories • conceptual framework or hierarchical structure
Computer packages for qualitative analysis • Good for sorting and searching, linking categories • e.g., ATLAS-ti, NUD*IST
Writing up the results • Different models • conventions for different genres of qualitative research • what best captures the essence of the data? • be guided by the research questions • Narrative account • tell a story • describe the phenomenon • illustrate with examples • Table of themes/ tree diagrams
Good practice in qualitative analysis • guidelines for evaluating qualitative research, e.g.: • credibility checks • have the research questions been answered? • is the analysis coherent and integrated? Elliott et al. (1999); Willig (2001); Yardley (2000)
Quantitative approaches • Measures of strength and significance of the findings
Statistical conclusion validity • Was the study sensitive enough? • Large enough sample? • Error minimised in measurement and design? • Do the variables covary? • Were the statistical methods appropriate? • If so, how strongly? • Significance (Shadish, Cook & Campbell, 2002)
Significance of the findings • Statistical significance • Effect sizes • Clinical significance
Statistical significance • p-value (alpha level) of statistic • e.g., 2 (1) = 4.7, p = 0.03 • null hypothesis testing framework • currently controversial • replace with confidence intervals? • value dependent on sample size
Effect size • measure of magnitude • independent of sample size • depends on statistical test • often classified into small, medium and large (see Cohen)
Effect sizes: Meta-analysis • Pioneered by Smith & Glass (1977) • Aggregates several studies, using effect sizes • Advantages: • Quantitative effect size index • Can also examine study variables (e.g., investigator allegiance) • However: GIGO (garbage in, garbage out)!
Clinical significance • Measure of meaningfulness • do patients actually improve? • “endstate functioning” • Jacobson and Truax (1991) • reliable change • clinical significance cut-offs • “Number needed to treat” • used in evidence-based medicine
External validity • Can the findings be generalised across: • persons • settings • times? • Replication • Literal • Operational • Constructive
How research is used and interpreted • Dissemination • research as a public activity • feedback to staff and managers • feedback to participants • Publication • Research utilisation • does research affect policy? • models of research utilisation (Weiss, 1986) • Political issues