4.1 Standard practices for measuring the economic performance of investments in buildings and building systems have been published by ASTM. A computer program that produces economic measures consistent with these practices is available.4 Discount Factor Tables has been published by ASTM to facilitate computing measures of performance for most of the practices.

4.2 This guide can be used to: (1) identify types of building design and system decisions that require economic analysis; (2) match the technically appropriate economic methods with the decisions; and (3) locate the methods in the ASTM practices and adjuncts listed in Section 2.

4.3 More than one method can be technically appropriate for many building decisions. Therefore the choice in practice of which technically appropriate economic method to use for evaluating a particular building decision will often depend on the perspective of the user. Some examples of factors that influence the user are: (1) ease of applying the methods, (2) level of familiarity of the user with the methods, (3) preference of the user for different methods, and (4) presence of budget limitations for the projects.

4.4 This guide identifies some features and limitations of the methods that might influence users' choices under varying conditions.