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Published on: October 11, 2018
Predictive accuracy and explained variation
1Section of Clinical Biometrics, Department of Medical Computer Sciences, Vienna University, Spitalgasse 23, A-1090 Vienna, Austria. michael.scheper@akh-wien.ac.at
Statistics in Medicine
|July 11, 2003
Summary
This study introduces unified measures for predictive accuracy and explained variation in regression models. These metrics quantify how well covariates predict outcomes, even when significance is high.
Area of Science:
- Statistics
- Biostatistics
- Epidemiology
Background:
- Predictive accuracy quantifies how well covariates determine individual outcomes in regression models.
- Explained variation measures the relative improvement in prediction accuracy when using covariates compared to unconditional prediction.
Purpose of the Study:
- To present a unified concept of predictive accuracy and explained variation.
- To provide measures applicable to various outcome types (continuous, binary, polytomous, survival).
- To demonstrate applications using examples from different regression models.
Main Methods:
- Development of a unified concept based on absolute prediction error.
- Formulation of measures in both model-based and observed-vs-expected contrasts.
- Application examples across continuous, binary, polytomous, and survival regression models.
Main Results:
- A unified framework for assessing predictive accuracy and explained variation is presented.
- Measures are applicable across diverse regression model types and outcome variables.
- Demonstrated that predictive accuracy can be low even with significant covariates.
Conclusions:
- The proposed unified measures offer a consistent approach to evaluating regression model performance.
- Emphasizes that statistical significance and effect size of covariates do not always translate to high predictive accuracy.
- Highlights the importance of assessing absolute and relative predictive accuracy in regression analysis.
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