Different ways of measuring code complexity

Oct 19, 2023

In the vast realm of software engineering, the quality of code is paramount. But how do we define and measure the quality of code? One of the critical aspects is understanding its complexity. Code complexity can significantly impact the maintainability, readability, and efficiency of software. As Robert C. Martin aptly pointed out, “the ratio of time spent reading versus writing is well over 10 to 1.” This emphasizes the importance of writing clear, concise, and maintainable code.

Understanding and measuring code complexity is essential for both the engineering team and stakeholders. It provides insights into potential bottlenecks, areas of optimization, and overall team performance. Let's delve into the different metrics used to gauge code complexity and understand why they matter.

Cyclomatic Complexity

This metric measures the number of linearly independent paths through a program's source code. In simpler terms, it gauges the number of decisions a program makes. A higher cyclomatic complexity indicates that the software might be harder to maintain and understand.

Lines of Source Code (LOC)

LOC is a straightforward metric that counts the number of lines in a program. While it provides a quick overview, relying solely on LOC can be misleading as not all lines of code contribute equally to complexity.

Lines of Executable Code

Unlike LOC, this metric focuses only on the lines of code that can be executed, excluding comments and whitespace. It offers a more accurate representation of the code that impacts the software's functionality.

Coupling/Depth of Inheritance

Coupling refers to the interdependence between software modules. High coupling can make the code harder to modify. Depth of Inheritance, on the other hand, measures the inheritance levels in object-oriented programming. A deeper inheritance can lead to increased complexity.

Maintainability Index

This metric combines various measurements like cyclomatic complexity, lines of code, and comments to produce an index that indicates how maintainable a piece of software is. A higher index suggests better maintainability.

Cognitive Complexity

Introduced by SonarSource, cognitive complexity measures how hard the code is for a human to understand. It considers loops, conditionals, and other factors that can make code harder to read.

Halstead Volume

Proposed by Maurice Howard Halstead, this metric combines the number of operations and operands in the code. It provides insights into the potential effort required to understand and maintain the code.

Code Churn

Refers to the percentage of a developer's recent edits (over some time period) compared to the total size of the codebase. High churn rates can indicate areas of high complexity or instability in the code.

Rework Ratio

This metric measures the amount of code that has to be reworked or modified after the initial development. A high rework ratio can indicate issues with code quality or the development process.

Why These Metrics Matter

For an engineering organization, understanding code complexity is crucial. It directly impacts the development process, the efficiency of code review, and the overall productivity of the development teams. By monitoring these metrics, engineering leaders can make informed decision-making processes, ensuring that the software is not only functional but also efficient and maintainable.

Moreover, these metrics play a pivotal role in continuous improvement. By identifying areas of high complexity, teams can focus on refactoring and optimization, ensuring that the software remains robust and scalable.

Harnessing Code Complexity Metrics with BuildPulse

To effectively measure and act upon these metrics, tools like BuildPulse Engineering Metrics are invaluable. BuildPulse not only provides comprehensive reporting on metrics like cycle time, pull requests, and dashboards but also acts as a developer copilot, notifying about stale pull requests and automating the review process. By leveraging such tools, engineering teams can ensure that their code remains of the highest quality, and any potential issues are promptly addressed.

In Conclusion

In the intricate world of software development, understanding code complexity is not a luxury but a necessity. It provides a roadmap for engineering teams, guiding them towards producing efficient, maintainable, and high-quality software. By leveraging the right metrics and tools, engineering teams can ensure that their code remains a paragon of excellence, driving business goals, ensuring customer satisfaction, and meeting the desired timeframe for delivery.