Little or no empirical validation exists for many of software engineering's basic assumptions. While some of these assumptions are intuitive, the need for scientific experimentation remains clear. Several assumptions are made about the factors affecting software reuse. In particular, the object-oriented paradigm and various human factors are hypothesized to affect the successful reuse of software components. This dissertation describes a controlled experiment designed to evaluate the impact of the object-oriented paradigm and human factors on software reuse. The human factors under investigation include managerial influence and cognitive abilities. This experiment concludes (a) the object-oriented paradigm makes significant contributions to productivity, (b) language differences are far more important when programmers reuse than when they do not, and (c) the object-oriented paradigm holds a particular affinity to the reuse process, (d) reuse results in higher productivity than no reuse independent of language paradigm, (e) the level of management encouragement does affect the reuse process, and (f) the cognitive ability of visualization does relate to effective reuse.