Exploring the effects of omitted variable bias in physics education research

Omitted variable bias occurs in most statistical models. Whenever a confounding variable that is correlated with both dependent and independent variables is omitted from a statistical model, estimated effects of included variables are likely to be biased due to omitted variables. This issue is parti...

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Autores principales: Cole Walsh, Martin M. Stein, Ryan Tapping, Emily M. Smith, N. G. Holmes
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Lenguaje:EN
Publicado: American Physical Society 2021
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spelling oai:doaj.org-article:3553fa02740a49ce869323f6437a550c2021-12-02T13:20:50ZExploring the effects of omitted variable bias in physics education research10.1103/PhysRevPhysEducRes.17.0101192469-9896https://doaj.org/article/3553fa02740a49ce869323f6437a550c2021-03-01T00:00:00Zhttp://doi.org/10.1103/PhysRevPhysEducRes.17.010119http://doi.org/10.1103/PhysRevPhysEducRes.17.010119https://doaj.org/toc/2469-9896Omitted variable bias occurs in most statistical models. Whenever a confounding variable that is correlated with both dependent and independent variables is omitted from a statistical model, estimated effects of included variables are likely to be biased due to omitted variables. This issue is particularly problematic in physics education research where many research studies are quasiexperimental or observational in nature due to ethical and logistical limitations. In this paper, we illustrate the mechanisms behind omitted variable bias in explanatory modeling using authentic data and analytical solutions. We demonstrate that omitting confounding variables that are strongly correlated with included variables and have large effects on the dependent variable can significantly bias estimated effects for included variables. We also find that controlling for variables that are uncorrelated with other variables or have no effect on the dependent variable does not appreciably bias estimated effects and may or may not affect the precision of those estimates. These results suggest that removing from explanatory models variables that are not “statistically significant” can have unintended consequences on model and variable interpretations. Our results underscore the importance of carefully considering why or why not to include a variable in a model, informed by both data and theory.Cole WalshMartin M. SteinRyan TappingEmily M. SmithN. G. HolmesAmerican Physical SocietyarticleSpecial aspects of educationLC8-6691PhysicsQC1-999ENPhysical Review Physics Education Research, Vol 17, Iss 1, p 010119 (2021)
institution DOAJ
collection DOAJ
language EN
topic Special aspects of education
LC8-6691
Physics
QC1-999
spellingShingle Special aspects of education
LC8-6691
Physics
QC1-999
Cole Walsh
Martin M. Stein
Ryan Tapping
Emily M. Smith
N. G. Holmes
Exploring the effects of omitted variable bias in physics education research
description Omitted variable bias occurs in most statistical models. Whenever a confounding variable that is correlated with both dependent and independent variables is omitted from a statistical model, estimated effects of included variables are likely to be biased due to omitted variables. This issue is particularly problematic in physics education research where many research studies are quasiexperimental or observational in nature due to ethical and logistical limitations. In this paper, we illustrate the mechanisms behind omitted variable bias in explanatory modeling using authentic data and analytical solutions. We demonstrate that omitting confounding variables that are strongly correlated with included variables and have large effects on the dependent variable can significantly bias estimated effects for included variables. We also find that controlling for variables that are uncorrelated with other variables or have no effect on the dependent variable does not appreciably bias estimated effects and may or may not affect the precision of those estimates. These results suggest that removing from explanatory models variables that are not “statistically significant” can have unintended consequences on model and variable interpretations. Our results underscore the importance of carefully considering why or why not to include a variable in a model, informed by both data and theory.
format article
author Cole Walsh
Martin M. Stein
Ryan Tapping
Emily M. Smith
N. G. Holmes
author_facet Cole Walsh
Martin M. Stein
Ryan Tapping
Emily M. Smith
N. G. Holmes
author_sort Cole Walsh
title Exploring the effects of omitted variable bias in physics education research
title_short Exploring the effects of omitted variable bias in physics education research
title_full Exploring the effects of omitted variable bias in physics education research
title_fullStr Exploring the effects of omitted variable bias in physics education research
title_full_unstemmed Exploring the effects of omitted variable bias in physics education research
title_sort exploring the effects of omitted variable bias in physics education research
publisher American Physical Society
publishDate 2021
url https://doaj.org/article/3553fa02740a49ce869323f6437a550c
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