کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1083348 | 950996 | 2009 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Instrumental variables I: instrumental variables exploit natural variation in nonexperimental data to estimate causal relationships Instrumental variables I: instrumental variables exploit natural variation in nonexperimental data to estimate causal relationships](/preview/png/1083348.png)
The gold standard of study design for treatment evaluation is widely acknowledged to be the randomized controlled trial (RCT). Trials allow for the estimation of causal effect by randomly assigning participants either to an intervention or comparison group; through the assumption of “exchangeability” between groups, comparing the outcomes will yield an estimate of causal effect. In the many cases where RCTs are impractical or unethical, instrumental variable (IV) analysis offers a nonexperimental alternative based on many of the same principles. IV analysis relies on finding a naturally varying phenomenon, related to treatment but not to outcome except through the effect of treatment itself, and then using this phenomenon as a proxy for the confounded treatment variable.This article demonstrates how IV analysis arises from an analogous but potentially impossible RCT design, and outlines the assumptions necessary for valid estimation. It gives examples of instruments used in clinical epidemiology and concludes with an outline on estimation of effects.
Journal: Journal of Clinical Epidemiology - Volume 62, Issue 12, December 2009, Pages 1226–1232