How to Evaluate Software Developers: Key Metrics, Technical Debt, and Code Quality

Learn how to evaluate software developers effectively using objective metrics. Discover the importance of technical debt and code quality in identifying top-performing developers for your team. Improve your evaluation process and ensure better team performance with data-driven insights.

How to Evaluate Software Developers: Key Metrics, Technical Debt, and Code Quality
key metrics for good developers

Evaluating developer performance should not rely on intuition but on objective metrics. Technical debt and code quality are essential factors in identifying a great developer within a team.

One of the most common mistakes made by project managers is the technical evaluation of developers. Despite being critical, it’s rare to find a project that doesn’t rely on the “CMVS” (or “How’s it going?”) technique. Conducting a professional evaluation requires updated metrics for each team member and the project.

To avoid relying on intuition or indefensible justifications for something that can’t be measured, it’s essential to always work with data. This ensures objectivity and provides a framework to support your team in the challenging situations every project faces.

How can you obtain effective project metrics?

Let’s start with the most commonly used metrics, which aren’t always the best:

Development Velocity

This metric comes from the Agile world and is often debated in our courses. It’s challenging to achieve this value without properly following Agile methodology or training the team to work as expected. It measures how many “story points” the team can complete per sprint (in Scrum). Applying this to a Kanban team is more complex. It requires time to establish, as it depends on the team’s level of self-organization. The more expertise a team has in working together, the more precise this metric becomes.

In a recent survey of 20 Scrum Masters and project managers, all evaluated individual developer performance based on the number of stories or tasks each member completed. This conflicts with Agile principles, as stories are multidisciplinary and require multiple contributors. Additionally, they didn’t clarify the context of the stories, leading to evaluations based more on intuition than objective measures.

Another common method is to measure stories in hours, which can be done in two ways: either the project manager decides the duration of each story, or it’s decided collaboratively by the team. While the latter fosters collaboration, it doesn’t improve accuracy. Daniel Kahneman, a Nobel laureate, explored this in his thesis on the “Planning Fallacy,” which describes the human tendency to underestimate task durations, even when similar tasks have taken longer in the past. It’s proven that estimating tasks longer than a day is inherently unreliable. If you want to deceive yourself, continue using this system.

Technical Debt

This is a popular factor for evaluating a developer’s technical contribution. It involves measuring the impact a developer has—consciously or not—on the project’s performance. Technical debt arises with each commit, whether due to poor practices, outdated frameworks, or inadequate testing.

Technical Debt Formula:

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Technical Debt = (Repair Cost / Development Cost) x 100%

Indirect methods to measure technical debt include:

• Detecting reduced development velocity.

• Measuring user satisfaction differences.

However, our job is to prevent technical debt, not just measure it.

Direct methods include:

• Bug increases per sprint, including unresolved bugs from previous sprints.

• Code complexity: Even bug-free code can suffer if it doesn’t follow principles like Clean Code or SOLID. Poor design increases maintenance burdens, delays new features, and raises cognitive load for developers. Factors such as poorly defined requirements, monolithic architectures, excessive modularization, or unnecessary use of new frameworks also exacerbate complexity.

What Defines a Good Developer?

If you’ve read this far, you know the answer: a good developer generates less technical debt.

A good developer isn’t necessarily the most communicative, the one who dominates meetings, or the most punctual. Instead, they:

• Commit after proper analysis.

• Fulfill commitments without sacrificing code quality.

• Maintain over 90% code coverage (unit testing).

• Produce minimal bugs per sprint, adhering to Clean Code and SOLID principles.

• Open their work to code reviews.

• Show curiosity for new frameworks and architectures, evaluating their risks before adoption.

• Address and propose fixes for poor practices or obfuscated code.

While these traits define a good developer, no single individual can excel alone due to the inevitable impediments in projects. Cognitive load is a primary challenge.

This is why a Squad or Minimum Viable Technical Team (MVTT) is essential to ensure project viability. While the investment is higher, the risk of not delivering a product on time is far more costly. If you have any questions, we’re here to help.