Some managers think that it’s important to have lots of programmers working on a project.  After all, the more people you have, the faster it will get done!  But nine pregnant women can’t make a baby in a month.

Adding more people to a late software project makes it later.  – Fred Brooks

In fact, large software teams lead to project stagnation.  Doug Putnam published research from 491 software projects.  His research demonstrates that as a team gets smaller, its overall productivity increases:

And the effort to deliver a software project rises exponentially with the size of the development team:

This seems to be a very nonintuitive result.  How can it be that adding more people to a project makes it worse?

The answer is that software development requires tight communication between all members of the team.  A team of 2 requires only a single communication channel.  But for a team of 7 people, 21 different communication channels are required.  Each member of the team must sync with each other member so that everyone stays on the same page.  As new developers are brought on board, they must be caught up to speed by existing developers who are taking time away from new work to educate others.  Pretty soon, everyone is in meetings, writing documentation, managing wikis, sending e-mails, and trying to communicate with everyone else instead of moving the project forward.  It is not uncommon for members of large teams to spend 80-90% of their time on communicative tasks.  As a result, progress stagnates, and the schedule slips.

A team of just 2 or 3 developers, on the other hand, is a productive team.  With only a few communication channels, each member can spend most of his or her time working on the project instead of answering the questions of other team members.  Meetings can be reduced to just an hour or two per week, and extensive documentation can be replaced with lightweight communication tools.  Small teams appear less impressive, but they ultimately get more done.

At DrewCrawfordApps we deploy small teams on our development projects to deliver quality software quickly and reliably at a pace that outstrips large teams with dozens of developers.  The next time you are thinking about using a large team for a project, consider whether that team will be as productive as a lightweight and agile team without the additional communication overhead.