Among the main activities involved in COTS-based development there are identification, evaluation, and selection of COTS products. Several techniques have been developed for these activities; all of them are based on measurement of attributes. The effort devoted to these activities is more valuable if the attributes can be reused. Since the evaluation of COTS is a very project-specific activity, the definition of reusable attributes is difficult. Several studies show that it is possible and convenient to develop a reusable attribute framework. We propose a set of simple and generic criteria can be used to validate the set of attributes and improve them.