For all types of statistical models, institutions must ensure that samples used for modelling are representative of the target variable to be modelled. Samples must meet minimum statistical properties to be eligible for modelling including, amongst others, a minimum size and a minimum number of data points.
6.5.2
Once a modelling data set has been identified, institutions should use sampling techniques to increase the likelihood of model stability, when possible. The sampling technique must be appropriate to the data set and a justification must be provided. Amongst others, common techniques include dividing data sets into a development sample and a validation sample.