Reviews of techniques are also more common in investment industry literature. McLean (1998) traces the development of credit risk measurement methods over the 1977–1997 period, ranging from subjective to quantitative. Kao (1999) provides an overview of several methods, Altman Z-scores, statistical models, structural and reduced form models (both default-based and transition-matrix-based), and market implied models. Jarrow, as summarized by Smith (1998), provides a nontechnical overview of credit derivatives and computation methods for pricing them. Van Deventer (2005) compares structural, reduced form and hybrid models, tests them using the Receiver Operating Characteristic Accuracy Ratio, and supports using a multiple model approach, that is, both structural and various implementations of reduced form models. Lleo (2009) reviews five main credit risk measurement methodologies: credit migration, structural models, intensity models, actuarial approaches, and large portfolio models.