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Beware of R2: Simple, Unambiguous Assessment of the Prediction Accuracy of QSAR and QSPR Models

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Alexander, D. L. J., Tropsha, A., Winkler, David A.·2015·Journal of Chemical Information and Modeling

Abstract

The statistical metrics used to characterize the external predictivity of a model, i.e., how well it predicts the properties of an independent test set, have proliferated over the past decade. This paper clarifies some apparent confusion over the use of the coefficient of determination, R(2), as a measure of model fit and predictive power in QSAR and QSPR modeling. R(2) (or r(2)) has been used in various contexts in the literature in conjunction with training and test data for both ordinary linear regression and regression through the origin as well as with linear and nonlinear regression models. We analyze the widely adopted model fit criteria suggested by Golbraikh and Tropsha ( J. Mol. Graphics Modell. 2002 , 20 , 269 - 276 ) in a strict statistical manner. Shortcomings in these criteria are identified, and a clearer and simpler alternative method to characterize model predictivity is provided. The intent is not to repeat the well-documented arguments for model validation using test data but rather to guide the application of R(2) as a model fit statistic. Examples are used to illustrate both correct and incorrect uses of R(2). Reporting the root-mean-square error or equivalent measures of dispersion, which are typically of more practical importance than R(2), is also encouraged, and important challenges in addressing the needs of different categories of users such as computational chemists, experimental scientists, and regulatory decision support specialists are outlined.

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Metadata

Authors
Alexander, D. L. J., Tropsha, A., & Winkler, D. A.
Venue
Journal of Chemical Information and Modeling
Published
2015-07-09
Volume
55
Issue
7
Pages
1316-1322
ISSN
  • 1549-9596 (ISSN-L)
  • 1549-960X
OpenAlex
W2294467502
Cited by
745
References
20
FWCI
36.93
Type
journal article
Language
en
Open access
green

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CoChat. (2026). Citation check: Beware of R2: Simple, Unambiguous Assessment of the Prediction Accuracy of QSAR and QSPR Models. https://app.cochat.ai/papers/10.1021/acs.jcim.5b00206
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Alexander, D. L. J., Tropsha, A., & Winkler, D. A. (2015). Beware of R2: Simple, Unambiguous Assessment of the Prediction Accuracy of QSAR and QSPR Models. Journal of Chemical Information and Modeling. https://doi.org/10.1021/acs.jcim.5b00206

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