Dataset Information

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 bias in the estimation of causal effects can result from applying the conventional IV method in inherently nonlinear regression settings. Moreover, the bias is not attenuated as the sample size increases. This point is further illustrated in the survey data analyses in which IV-based estimates of the relevant causal effects diverge substantially from those obtained with appropriate nonlinear estimation methods.

Conclusions

We offer this research as a cautionary note to those who would opt for the use of linear specifications in inherently nonlinear settings involving endogeneity.

SUBMITTER: Terza JV

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

REPOSITORIES: biostudies-literature

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Publications

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

Terza Joseph V JV Bradford W David WD Dismuke Clara E CE

Health services research 20080601 3

<h4>Objective</h4>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.<h4>Data sources</h4>Smoking Supplement to the 1979 National Health Interview Survey, National Longitudinal Alcohol Epidemiologic Survey, and simulated data.<h4>Study design</h4>Potential bias from the use of the linear IV method in nonlinear models is assessed via simulation studies and real worl ...[more]

PMID: 18546544

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Project description:BackgroundTo describe the ethical issues and experiences of scientists conducting mixed methods health services research and to advance empirical and conceptual discussion on ethical integrity in mixed methods health research.MethodsThe study was conducted with 64 scholars, faculty and consultants from the NIH-funded Mixed Methods Research Training Program (MMRTP) for the Health Sciences. This was a cross-sectional study. Survey results were analyzed using descriptive statistics to characterize responses and open coding to summarize strategies about eight ethical mixed methods research issues. Respondents completed an online survey to elicit experiences related to eight ethical issues (informed consent, confidentiality, data management, burden, safety, equitable recruitment, communication, and dissemination) and strategies for addressing them.ResultsOnly about one-third of respondents thought their research ethics training helped them plan, conduct, or report mixed methods research. The most frequently occurring ethical issues were participant burden, dissemination and equitable recruitment (> 70% endorsement). Despite occurring frequently, < 50% of respondents rated each ethical issue as challenging. The most challenging ethical issues were related to managing participant burden, communication, and dissemination. Strategies reported to address ethical issues were largely not specific or unique to mixed methods with the exception of strategies to mitigate participant burden and, to a lesser degree, to facilitate equitable recruitment and promote dissemination of project results.ConclusionsMixed methods health researchers reported encountering ethical issues often yet varying levels of difficulty and effectiveness in the strategies used to mitigate ethical issues. This study highlights some of the unique challenges faced by mixed methods researchers to plan for and appropriately respond to arising ethical issues such as managing participant burden and confidentiality across data sources and utilizing effective communication and dissemination strategies particularly when working with a multidisciplinary research team. As one of the first empirical studies to examine mixed methods research ethics, our findings highlight the need for greater attention to ethics in health services mixed methods research and training.

Dataset Information

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

Objective

Data sources

Study design

Principal findings

Conclusions

Publications

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

Similar Datasets

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