(82)As no particular method for the calculation of the probability distribution forecast for internal models is prescribed in accordance with Article 121(4) of Directive 2009/138/EC and as internal models should be adapted to the specific business of the insurance and reinsurance undertaking, internal models may vary significantly in their methodology, the information, assumptions and data used for the internal model and in their validation processes. The statistical quality standards and the validation standards should therefore remain principle-based and include only specific minimum requirements. For the same reason, the documentation standards should not include a complete list of documents, but only a minimum list of documents that should exist for each internal model. Undertakings' documentation should contain any additional information that is necessary to comply with the documentation standards for internal models.