An experiment about static and dynamic type systems

Abstract

Although static type systems are an essential part in teaching and research in software engineering and computer science, there is hardly any knowledge about what the impact of static type systems on the development time or the resulting quality for a piece of software is. On the one hand there are authors that state that static type systems decrease an application's complexity and hence its development time (which means that the quality must be improved since developers have more time left in their projects). On the other hand there are authors that argue that static type systems increase development time (and hence decrease the code quality) since they restrict developers to express themselves in a desired way. This paper presents an empirical study with 49 subjects that studies the impact of a static type system for the development of a parser over 27 hours working time. In the experiments the existence of the static type system has neither a positive nor a negative impact on an application's development time (under the conditions of the experiment).