Multivariate graphical methods provide an insightful way to formulate explanatory hypotheses from limited categorical data

• Published in: Journal of clinical epidemiology Vol. 65; no. 2; pp. 179 - 188
• Main Authors: Van Ness, Peter H, Murphy, Terrence E, Araujo, Katy L.B, Pisani, Margaret A
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.02.2012; Elsevier; Elsevier Limited
• Subjects: Adult and adolescent clinical studies; Aged; Aged, 80 and over; Anxiety disorders. Neuroses; Biological and medical sciences; Critical Care; Data Display; Epidemiology; Female; Graphical methods; Humans; Hypotheses; Intensive care; Internal Medicine; Logic; Male; Medical sciences; Methods; Middle Aged; Multivariate Analysis; Multivariate data; Older patients; Post-traumatic stress disorder; Posttraumatic stress disorder; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Statistics as Topic; Stress Disorders, Post-Traumatic - complications; Studies; Older patients; Critical care; Posttraumatic stress disorder; Multivariate data; Logic; Graphical methods; Human; Methodology; Anxiety disorder; Patient; Method; Hypothesis; Care; Stress; Graphics; Limit; Elderly
• ISSN: 0895-4356; 1878-5921
• DOI: 10.1016/j.jclinepi.2011.06.007

Abstract Objective Graphical methods for generating explanatory hypotheses from limited categorical data are described and illustrated. Study Design and Setting Univariate, bivariate, multivariate, and multiplicative graphical methods were applied to clinical data regarding very ill older persons. The data to which these methods were applied were limited as to their nature (e.g., nominal categorical data) or quality (e.g., data subject to measurement error and missing values). Such limitations make confirmatory inference problematic but might still allow for meaningful generation of new explanatory hypotheses in some cases. Results A striking feature of the graphical results from this study’s major illustrative application was that posttraumatic stress disorder (PTSD) after intensive care unit discharge occurred rarely and nearly always co-occurred with two or more other mental health conditions. These results suggest the explanatory hypothesis that PTSD in this context is less attributable to single traumatic causes than to acute illnesses contributing to a cascade of mental health decrements. Conclusion Illustrative applications of a sequence of graphical procedures yield more informative and less abstract representations of limited data than do descriptive statistics alone, and by doing so, they aid in the formulation of explanatory hypotheses.