A friend of mine grew up on a family farm where he and his cousins would often help their grandfather with weekend projects. But whenever all three cousins wanted to work together, the grand­father would protest: "One boy is a boy, two boys is half a boy, and three boys ain't no boy at all." 

This wasn't so much a criticism of teamwork as a commentary on the behavior of male adolescents. Still, there's an important lesson in his logic: Adding more people to a project does not necessarily make it better. And when it comes to creative problem solving, more people often does just the opposite.

I was reminded of this recently in my company. Our headquarters has a staff of 10, and most of us have worked together for more than a decade. But a few months ago, we noticed that it was taking us far too long to make decisions, to respond to challenges, and to come up with new ideas during our meetings, which usually included everyone.

So we decided to break the company into three functional groups: one focused on clients, another on content, and a third on operations. Within days--yes, days­--of making this difficult change, we generated more new ideas and solved more lingering problems than we had in the prior six months.

For example, our new, more nimble client team now meets weekly to discuss issues facing our customers and the progress we're making in addressing those issues. Previously, when the discussions included the entire office, there had never been enough time for a full back-and-forth, meaning that some ideas and potential solutions never got aired.

Likewise, now that decisions are being made by four people instead of 10, the content team was able to release a new Web-based tool for our clients, as well as produce a series of instructional videos­--all within two weeks.

And by cutting back on the number of people involved in making operational decisions, we've managed to simplify some of those processes, especially in our financial department. Now we've outsourced part of that department to a trusted contractor, allowing my people more time to focus on their primary responsibilities.

Having made these seemingly simple changes, our passion for what we do has reignited. We didn't have to hire anyone or let anyone go. We just had to get back to small-group innovation. More than anything, that requires healthy conflict, constructive tension, and productive friction. Without a significant amount of debate and deliberation, which is difficult in large groups, new ideas cannot be born.

I've seen it again and again in my consulting: Most teams are too large to be innovative, despite their leaders' best intentions. If you really want to step up your team's creative thinking, take a hard look at how many people you're putting in a room together. More than three to five is probably too many. Smaller groups of people can establish trusting relationships. They learn to be vulnerable with one another, and get accustomed to being uncomfortable. They can say things among themselves, without great drama, that polite colleagues would find appalling. As a result, they sift through and evaluate more ideas in minutes and hours than larger groups, saddled with bureaucracy and protocol, can take on in months.

Which brings me back to my friend's grandfather. He would probably summarize our experience this way: "Four people is an innovator, 7 people is half an innovator, and 10 people ain't no innovator at all."

From the June 2015 issue of Inc. magazine