The milestones of the history of software development are paradigm shifts. Each paradigm brought its own features and new ways of composing them to assemble software systems. Understanding the impact of paradigm shifts encompasses making comparisons among systems built with different paradigms. Performing this kind of assessments is a very difficult exercise since the characterization of software assets is generally performed using paradigm-specific quantifications. In this paper we propose a metamodel for describing software products (either source code or design models) that is paradigm-independent. This metamodel, combined with a formal quantification approach, can help performing paradigm-independent software systems assessment. We illustrate the use of the proposed metamodel on a case study comparing functionally-equivalent systems produced with OOP and AOP.