title: Toward rigorous idiographic research in prevention science: comparison between three analytic strategies for testing preventive intervention in very small samples.
abstract: Psychosocial prevention research lacks evidence from intensive within-person lines of research to understand idiographic processes related to development and response to intervention. Such data could be used to fill gaps in the literature and expand the study design options for prevention researchers, including lower-cost yet rigorous studies (e.g., for program evaluations), pilot studies, designs to test programs for low prevalence outcomes, selective/indicated/adaptive intervention research, and understanding of differential response to programs. This study compared three competing analytic strategies designed for this type of research: autoregressive moving average, mixed model trajectory analysis, and P-technique. Illustrative time series data were from a pilot study of an intervention for nursing home residents with diabetes (N = 4) designed to improve control of blood glucose. A within-person, intermittent baseline design was used. Intervention effects were detected using each strategy for the aggregated sample and for individual patients. The P-technique model most closely replicated observed glucose levels. ARIMA and P-technique models were most similar in terms of estimated intervention effects and modeled glucose levels. However, ARIMA and P-technique also were more sensitive to missing data, outliers and number of observations. Statistical testing suggested that results generalize both to other persons as well as to idiographic, longitudinal processes. This study demonstrated the potential contributions of idiographic research in prevention science as well as the need for simulation studies to delineate the research circumstances when each analytic approach is optimal for deriving the correct parameter estimates.
authors.affiliation: Department of Pharmaceutical Sciences, Center for Education and Drug Abuse Research, University of Pittsburgh, 3520 Forbes Avenue, 2nd Floor, Room 226, Pittsburgh, PA 15213, USA. tar27@pitt.edu
authors.forename: Ty A
authors.initials: TA
authors.lastname: Ridenour
authors.forename: Thomas Z
authors.initials: TZ
authors.lastname: Pineo
authors.forename: Mildred M
authors.initials: MM
authors.lastname: Maldonado Molina
authors.forename: Kristen
authors.initials: K
authors.lastname: Hassmiller Lich
mesh_terms: D003920:Diabetes Mellitus / Q000517:prevention & control; D006801:Humans; D011315:Preventive Medicine