External validation is necessary in prediction research:

A note on a general definition of the coefficient of determination

N. J. D. Nagelkerke · Biometrika · 1991 · 5.7K citations

Business, Biostatistics, Statistical Modeling +12

Internal validation of predictive models

Ewout W. Steyerberg, Frank E. Harrell, Gerard Borsboom et al. · Journal of Clinical Epidemiology · 2001 · 2.6K citations

Computing, Computer Science, Machine Learning +13

Estimating the Error Rate of a Prediction Rule: Improvement on Cross-Validation

Bradley Efron · Journal of the American Statistical Association · 1983 · 2.2K citations

Computing, Computer Science, Machine Learning +15

Improvements on Cross-Validation: The 632+ Bootstrap Method

Bradley Efron, Robert Tibshirani · Journal of the American Statistical Association · 1997 · 1.4K citations

Computing, Computer Science, Data Science +17

Assessing the Generalizability of Prognostic Information

Amy C. Justice · Annals of Internal Medicine · 1999 · 1.2K citations

Medicine, Oncology, Clinical Classification Systems +14