Validation is an essential step of QSAR modeling, and it can be performed by both internal validation techniques (e.g., cross-validation, bootstrap) or by an external set of test objects, that is, objects not used for model development and/or optimization. The evaluation of model predictive ability is then completed by comparing experimental and predicted values of test molecules. When dealing with quantitative QSAR models, validation results are generally expressed in terms of Q2 metrics. In this work, four fundamental mathematical principles, which should be respected by any Q2 metric, are introduced. Then, the behavior of five different metrics (QF12, QF2 2, QF3 2, QCCC2, and QRm2) is compared and critically discussed. The conclusions highlight that only the QF32 metric satisfies all the stated conditions, while the remaining metrics show different theoretical flaws.

Todeschini, R., Ballabio, D., Grisoni, F. (2016). Beware of Unreliable Q2! A Comparative Study of Regression Metrics for Predictivity Assessment of QSAR Models. JOURNAL OF CHEMICAL INFORMATION AND MODELING, 56(10), 1905-1913 [10.1021/acs.jcim.6b00277].

Beware of Unreliable Q2! A Comparative Study of Regression Metrics for Predictivity Assessment of QSAR Models

TODESCHINI, ROBERTO
Primo
;
BALLABIO, DAVIDE
Secondo
;
GRISONI, FRANCESCA
Ultimo
2016

Abstract

Validation is an essential step of QSAR modeling, and it can be performed by both internal validation techniques (e.g., cross-validation, bootstrap) or by an external set of test objects, that is, objects not used for model development and/or optimization. The evaluation of model predictive ability is then completed by comparing experimental and predicted values of test molecules. When dealing with quantitative QSAR models, validation results are generally expressed in terms of Q2 metrics. In this work, four fundamental mathematical principles, which should be respected by any Q2 metric, are introduced. Then, the behavior of five different metrics (QF12, QF2 2, QF3 2, QCCC2, and QRm2) is compared and critically discussed. The conclusions highlight that only the QF32 metric satisfies all the stated conditions, while the remaining metrics show different theoretical flaws.
Articolo in rivista - Articolo scientifico
QSAR; chemometrics; validation; Q2
English
2016
56
10
1905
1913
reserved
Todeschini, R., Ballabio, D., Grisoni, F. (2016). Beware of Unreliable Q2! A Comparative Study of Regression Metrics for Predictivity Assessment of QSAR Models. JOURNAL OF CHEMICAL INFORMATION AND MODELING, 56(10), 1905-1913 [10.1021/acs.jcim.6b00277].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/134595
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