The use of linear instrumental variables methods in health services research and health economics: a cautionary note.

ABSTRACT:

Objective

To investigate potential bias in the use of the conventional linear instrumental variables (IV) method for the estimation of causal effects in inherently nonlinear regression settings.

Data sources

Smoking Supplement to the 1979 National Health Interview Survey, National Longitudinal Alcohol Epidemiologic Survey, and simulated data.

Study design

Potential bias from the use of the linear IV method in nonlinear models is assessed via simulation studies and real world data analyses in two commonly encountered regression setting: (1) models with a nonnegative outcome (e.g., a count) and a continuous endogenous regressor; and (2) models with a binary outcome and a binary endogenous regressor.

Principal findings

The simulation analyses show that substantial

SUBMITTER: Terza JV 

PROVIDER: S-EPMC2442231 | biostudies-literature | 2008 Jun

REPOSITORIES: biostudies-literature