Empirical research is one way of testing software engineering methodologies. Many claims of the advantages of the object oriented paradigm have been made by research. Our work involves empirical projects in an attempt to validate these claims. This paper describes an experiment which compares the maintainability of the two functionally equivalent systems in order to explore the claim that systems developed with object-oriented languages are more easily maintained than those programmed with procedural languages. We found supporting evidence that programmers produce more maintainable code with an object-oriented language than with a standard procedural language. Another on-going research effort attempts to measure the reusability of objects (written in C++) versus the reusability of procedures (written in Pascal). These experiments involve students, but unlike other published reports, deal with large systems.