Modifiability measurement from a task complexity perspective: A feasibility study

Despite the critical role of software modifiability, it has no universally accepted measurement model. Measuring modifiability in terms of maintenance effort is problematic because it confounds modifiability with the ability of individual maintainers. In this paper, we apply Wood's task complexity model to propose a general analytical model that describes the characteristics of maintenance tasks and the analytical dimensions of modifiability independent of the individual maintainers. The results of a case study demonstrate the construct validity of the model.

1. Introduction

Developing software that is easy to change is difficult. Due to constantly evolving requirements and hardware, most software is modified many times after its first release. Recent studies report that more than 90% of software costs are caused by maintenance and evolution [1]. Therefore, stakeholders expect a system to be designed so that it can be changed quickly and economically. This quality is referred as modifiability.