Quantitative Analysis of the Effects of Technical Debt Accumulation on Long-Term Software Maintainability Using Longitudinal Case Studies of Open-Source Projects

Abstract

Technical debt (TD) represents the long-term cost incurred by prioritizing quick software releases over sound engineering practices. While prior studies have established its negative effects, empirical insights into how TD accumulates and affects long-term maintainability are still fragmented. This paper presents a quantitative, longitudinal analysis across multiple mature open-source software (OSS) projects. By examining repositories over time, we assess the correlation between TD growth and maintainability degradation. The study leverages metrics such as code complexity, issue resolution time, and commit frequency. Results reveal that sustained TD accumulation leads to a measurable decline in maintainability, often surfacing as increased bug density and reduced development velocity. Our findings provide actionable insights for engineering teams seeking to manage TD in evolving codebases.