Finally, several papers provide cautions regarding modeling. Klein et al. (2009) view one of the causes of the financial crisis to be overreliance on third-party credit ratings by companies and regulators. Schoolman (2008) states that both Wall Street and insurers tend to underestimate risk, especially with respect to new, innovative securities and warns that historical data should include stressed periods, and model review should include specific stresses (particularly on correlation assumptions).
2
Derman (2009) provides a caution regarding the overreliance on models, "To confuse the model with the world is to embrace a future disaster driven by the belief that humans obey mathematical rules."
2 Schoolman