On the relationship between source-code metrics and cognitive load: A systematic tertiary review

Abstract

The difficulty of software development tasks depends on several factors including the characteristics of the underlying source-code. These characteristics can be captured and measured using source-code metrics, which, in turn, can provide indications about the difficulty of the source-code. From a cognitive perspective, this difficulty is due to an increase in developers’ cognitive load, which can be estimated using psycho-physiological measures. Based on these measures, a handful of studies investigated the relationship between source-code metrics and cognitive load. For most of the metrics, such a relationship could not be established. While these studies used a small subset of metrics, the literature comprises hundreds of other metrics. Despite the existing reviews surveying these metrics, a consolidated overview is still needed to understand their properties and leverage their potential to align with cognitive load. This need is addressed in this paper through a Systematic Tertiary Review (STR) covering the full spectrum of source-code metrics, studying their properties and investigating their potential relationship to cognitive load. The outcome of this STR is intended to guide practitioners in choosing appropriate metrics, set the grounds for conceptualizing the relationship between source-code metrics and cognitive load and raise new research challenges for the future.