Twice as Many Devs Won’t Deliver Twice as Much Code — On Correlation vs Causation

In the world of software development, we often hear the phrase “more hands make light work.” However, when it comes to adding developers to a project, this adage doesn’t hold as much water as one might hope. In fact, the relationship between the number of developers and the amount of code produced is not as straightforward as it may seem. In this post, we’ll explore the nuances of adding developers to a project, the concept of diminishing returns, and the importance of understanding correlation versus causation in tech projects.

The Myth of Linear Productivity

One of the most common misconceptions in software development is that doubling the number of developers will result in doubling the output of code. While it seems logical, the reality is often quite different. As more developers are added to a project, the complexity of coordination and communication increases exponentially. As a result, the productivity of the team does not scale linearly. This phenomenon is known as diminishing returns.

Diminishing Returns in Action

When you add developers to a project, you may initially see a boost in productivity. However, as more developers join the team, the overhead of communication and coordination can lead to a decrease in overall efficiency. Each new developer needs to be onboarded, brought up to speed, and integrated into the team’s processes. This can strain resources and lead to confusion, especially if the project lacks clear documentation and a well-defined workflow.

Moreover, with more developers, the likelihood of overlapping work increases. Developers may inadvertently step on each other’s toes, leading to wasted effort and frustration. This is particularly true in teams where roles and responsibilities are not clearly defined.

Finding Value in Collaboration

While adding developers can lead to diminishing returns, it doesn’t mean that there isn’t value in expanding the team under the right circumstances. The key is to approach resource allocation strategically. Here are some ways that adding developers can still provide significant value:

Parallel Work Streams

By adding developers, teams can take advantage of parallel work streams. For example, if there are multiple components of a project that can be developed simultaneously, having more developers allows the team to tackle these components at the same time. This can lead to faster overall progress even if the total lines of code produced do not double.

Pair Programming and Mentoring

As one commenter pointed out, adding developers can facilitate pair programming. This approach not only helps to keep the work moving forward when one developer is unavailable (due to illness or vacation) but also enhances learning opportunities for junior developers. Experienced developers can guide less experienced ones, leading to a stronger team in the long run.

Moreover, with two developers on a task, they can divide responsibilities—one can focus on writing tests or documentation while the other writes code. This collaborative approach can lead to a more robust and well-rounded product.

Educating Stakeholders on Spurious Correlations

It’s crucial for stakeholders and senior leadership to understand the concept of spurious correlations—the idea that just because two things occur together doesn’t mean that one causes the other. The assumption that more developers will lead to more code can be misleading.

Instead, teams should focus on efficient resource allocation, clear communication, and maintaining a sustainable pace of work. By emphasizing quality over quantity, teams can produce better products without falling into the trap of blindly increasing headcount.

Conclusion

In conclusion, while adding developers to a project may not result in a linear increase in output, it can still provide valuable benefits when done thoughtfully. Emphasizing collaboration, clear roles, and strategic planning can lead to more effective outcomes. Remember, it’s not just about the number of developers you have; it’s about how effectively they can work together to solve problems and deliver high-quality code.

Understanding the intricacies of correlation versus causation is essential for making informed decisions in software development. By fostering a culture of learning and collaboration, teams can thrive—regardless of their size.