Changeproneness

Changeproneness is a term used in software engineering to describe how susceptible a software module is to future modifications. A module with high changeproneness is expected to require more maintenance effort as requirements evolve, bugs are fixed, or refactoring occurs.

Measurement relies on historical data from version control systems and issue trackers. Common indicators include change frequency (how often a module is modified), churn (lines added or deleted), and change breadth (how many files or components are touched by a modification). Many studies convert these signals into a probability or risk score that a module will change in a given time window.

Factors that influence changeproneness include size and complexity (for example, high cyclomatic complexity), coupling and cohesion, the module's responsibilities, and the history of changes (age, volatility, number of contributors). Modules that are central in the dependency graph or that implement evolving features tend to be more change-prone.

Changeproneness is related to, but distinct from, defect proneness. It is often used in maintenance planning and risk assessment to prioritize code reviews, testing, refactoring, and documentation. Predictive models may couple changeproneness with other signals to estimate maintenance effort or to guide resource allocation.

Limitations include data quality, non-stationary processes, and the fact that past changes do not guarantee future ones. It is best used as one input among multiple risk indicators, and its utility improves when contextualized within project goals, development processes, and domain characteristics.