r2

synonym: $R^{2}$
https://doi.org/10.1351/goldbook.11499
The ratio of the sum of squares explained by a regression model (SSR) to the "total" sum of squares around the mean (SST), or, because SST equals SSR plus the sum of squares of the error or residuals from the fit (SSE): \[R^{2} = \frac{{\rm{SSR}}}{{\rm{SST}}} = 1 - \frac{{\rm{SSE}}}{{\rm{SST}}}\]
Notes:
  1. \(R_{2}\) values can range between \(\pu{0.0}\) and \(\pu{1.0}\).
  2. Except for the comparison of different models for the same dataset, \(R^{2}\) values are not a good indica- tion of fit of a model because the calculation depends on SST, which is larger if there is more spread in the observed values.
Source:
PAC, 2016, 88, 239. (Glossary of terms used in computational drug design, part II (IUPAC Recommendations 2015)) on page 254 [Terms] [Paper]
Citation: 'r2' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.11499 RIS BibTex EndNote
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