The application of sample selection models to outcomes research: the case of evaluating the effects of antidepressant therapy on resource utilization

✍ Scribed by William H. Crown; Robert L. Obenchain; Luella Englehart; Tamra Lair; Don P. Buesching; Thomas Croghan

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 120 KB
• Volume: 17
• Category: Article
• ISSN: 0277-6715
• DOI: 10.1002/(sici)1097-0258(19980915)17:17<1943::aid-sim885>3.0.co;2-0

✦ Synopsis

Non-randomized studies of treatment effects have come under criticism because of their failure to control for potential biases introduced by unobserved variables correlated with treatment selection and outcomes. This paper describes the basic concepts of sample selection modelsa technique used widely in the economics evaluation literature for nearly two decadesand discusses the potential role of these models in outcomes research. In addition, it presents a case study of the application of the sample selection modelling approach to evaluation of the effects of antidepressant therapies on medical expenditures for physician services. This case study presents empirical comparisons of alternative model specifications and discusses practical issues in evaluation of sample selection models. We demonstrate that, in this particular case, sample selection models yield very different conclusions regarding treatment effects than traditional ordinary least squares regression.