title: Connecting micro dynamics and population distributions in system dynamics models.
abstract: Researchers use system dynamics models to capture the mean behavior of groups of indistinguishable population elements (e.g., people) aggregated in stock variables. Yet, many modeling problems require capturing the heterogeneity across elements with respect to some attribute(s) (e.g., body weight). This paper presents a new method to connect the micro-level dynamics associated with elements in a population with the macro-level population distribution along an attribute of interest without the need to explicitly model every element. We apply the proposed method to model the distribution of Body Mass Index and its changes over time in a sample population of American women obtained from the U.S. National Health and Nutrition Examination Survey. Comparing the results with those obtained from an individual-based model that captures the same phenomena shows that our proposed method delivers accurate results with less computation than the individual-based model.
authors.affiliation: Assistant Professor of Industrial and Mechanical Engineering, California State Polytechnic University, Pomona, .
authors.forename: Saeideh
authors.initials: S
authors.lastname: Fallah-Fini
authors.affiliation: Associate Professor of Industrial and Systems Engineering Department, Virginia Tech.
authors.forename: Hazhir
authors.initials: H
authors.lastname: Rahmandad
authors.affiliation: Former post-doctoral Fellow, Department of International Health, Johns Hopkins, Bloomberg School of Public Health. Assistant Professor, Institute of Public Health, National, Yang-Ming University, Taiwan, ROC.
authors.forename: Hsin-Jen
authors.initials: HJ
authors.lastname: Chen
authors.affiliation: PhD Candidate at Johns Hopkins Global Center On Childhood Obesity, Johns Hopkins University Bloomberg School of Public Health. Research Assistant Professor, Department of Epidemiology and Environmental Health (formerly Department of Social and Preventive Medicine), School of Public Health and Health Professions, University at Buffalo, State University of New York.
authors.forename: Hong
authors.initials: H
authors.lastname: Xue
authors.affiliation: Chair and Professor, Department of Epidemiology and Environmental Health (formerly Department of Social and Preventive Medicine), University at Buffalo, State University of New York; Founding Director of the Johns Hopkins Global Center On Childhood Obesity, Adjunct Professor at Johns Hopkins University Bloomberg School of Public Health. Tel: 716-829-5383.
authors.forename: Youfa
authors.initials: Y
authors.lastname: Wang
keywords: Aggregation; Distribution; Heterogeneity; Individual-based; Multi-level