Assessing the quality of evolving Haskell systems by measuring structural inequality
Sander Kamps, Bastiaan Heeren, Johan T. Jeuring · 2020
Software metrics are used to measure the quality of a software system, and to understand the evolution of the system's quality over time. In this paper we report on an empirical study that investigates whether structural degradation in Haskell systems is related to decreasing software quality. For our study we use three metrics that measure internal attributes at the level of Haskell modules: intra-modular complexity (cohesion), inter-modular complexity (coupling), and module size. For these metrics, we calculate the Gini coefficient, which is a measure of the inequality in a distribution of values within a certain population, and the deviation of the population's central tendency from an empirically established ideal value. We develop a method to track the evolution, and measure the correlation between the calculated system-level information and post-release defects.