Source: Water Resources Research
An important part of a hydrologist’s training is the art and science of building parsimonious and robust hydrological models. An established methodology in robustness testing is calibrating a model with one part of the data and then validating it on the remaining part. This so-called “split sample approach” is a widely used and accepted procedure.
Shen et al. , however, suggest that this practice is likely flawed and should be discarded. Their impressive empirical study, using two hydrological models in 463 United States catchments and 50 different data splitting schemes, convincingly shows that all data should be used for model development and calibration before the model is implemented for decision making. Although this conclusion needs further testing with other model types, it is bound to shake hydrologic practice.
Citation: Shen, H., Tolson, B. A., & Mai, J. (2022). Time to update the split-sample approach in hydrological model calibration. Water Resources Research, 58, e2021WR031523. https://doi.org/10.1029/2021WR031523
—Marc F. P. Bierkens, Editor, Water Resources Research