TY - JOUR
T1 - Beware of Unreliable Q2! A Comparative Study of Regression Metrics for Predictivity Assessment of QSAR Models
AU - Todeschini, Roberto
AU - Ballabio, Davide
AU - Grisoni, Francesca
N1 - Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/10/24
Y1 - 2016/10/24
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84992723917&partnerID=8YFLogxK
U2 - 10.1021/acs.jcim.6b00277
DO - 10.1021/acs.jcim.6b00277
M3 - Article
C2 - 27633067
AN - SCOPUS:84992723917
SN - 1549-9596
VL - 56
SP - 1905
EP - 1913
JO - Journal of Chemical Information and Modeling
JF - Journal of Chemical Information and Modeling
IS - 10
ER -