title: Generalizing observational study results: applying propensity score methods to complex surveys.
abstract: OBJECTIVE
  To provide a tutorial for using propensity score methods with complex survey data.
  
  
  METHODS
  Simulated data and the 2008 Medical Expenditure Panel Survey.
  
  
  METHODS
  Using simulation, we compared the following methods for estimating the treatment effect: a naïve estimate (ignoring both survey weights and propensity scores), survey weighting, propensity score methods (nearest neighbor matching, weighting, and subclassification), and propensity score methods in combination with survey weighting. Methods are compared in terms of bias and 95 percent confidence interval coverage. In Example 2, we used these methods to estimate the effect on health care spending of having a generalist versus a specialist as a usual source of care.
  
  
  RESULTS
  In general, combining a propensity score method and survey weighting is necessary to achieve unbiased treatment effect estimates that are generalizable to the original survey target population.
  
  
  CONCLUSIONS
  Propensity score methods are an essential tool for addressing confounding in observational studies. Ignoring survey weights may lead to results that are not generalizable to the survey target population. This paper clarifies the appropriate inferences for different propensity score methods and suggests guidelines for selecting an appropriate propensity score method based on a researcher's goal.
authors.affiliation: Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, 624 N. Broadway, Rm 301, Baltimore, MD, 21205.
authors.forename: Eva H
authors.initials: EH
authors.lastname: Dugoff
authors.forename: Megan
authors.initials: M
authors.lastname: Schuler
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Stuart
mesh_terms: D003198:Computer Simulation; D003663:Decision Trees; D005102:Health Expenditures / Q000706:statistics & numerical data*; D006302:Health Services Research / Q000379:methods*; D006801:Humans; D057216:Propensity Score; D012107:Research Design; D011795:Surveys and Questionnaires
keywords: Survey research; health care costs; primary care