Amazon CEO Jeff Bezos has this rule: no meeting should be so large that two pizzas can’t feed the whole group. This is, of course, a shorthand method for ensuring that, as is often the case with big groups, no one’s ideas get drowned out. So is Bezos on to something or just hungry? We looked into it and, spoiler alert, there’s math involved. You’ve been warned.
Wipe the crust out of your eyes and get your head in the calzone because we’re about to dive deep, dish out all the saucy secrets, and leave you with some knead-to-know tips to achieve pie-in-the-sky meeting productivity and save your organization some dough!
Sorry … that was cheesy.
So how many people does two pizzas feed? According to an online pizza purchasing calculator (which is a real thing—the future is now), a medium 12” pizza is eight slices and feeds three to four (so, three) people. By that logic, the Two Pizza Rule dictates the ideal meeting size should have about six people (or eight people who are lying to themselves). But that assumes a medium pizza.
The pizza calculator puts a large 14” pie at between eight to ten slices and feeding three to ten people, so—just to be safe—we’re setting the range for group sizes under the Two Pizza Rule as being between six and ten people.
A Quick Acknowledgement
Before we get into the facts and figures, let’s acknowledge that a big group size won’t always cause the apocalyptic disruption to your organization that this article would otherwise suggest. A big group setting can be a great way to bring a team together. An interdepartmental check-in provides an opportunity for everyone to learn what everyone else is working on. It can also be used as a way to unify team members behind a larger initiatives.
The dangers of big groups are realized much more frequently in meetings where clear, concrete decisions need to be made; strategizing, positioning, etcetera; meetings where each group member expects to walk a way with a set of high-priority action items.
Trending Toward Disaster
It’s difficult, if not futile, to gather empirical support suggesting any single number is the ideal group size. That makes sense. The absolute minimum number of people needed for group deliberation depends entirely on the organization and the topics over which the group is deliberating.
Most of the research surrounding the role of group size in meeting productivity and decision-making effectiveness focuses on quantifying a trend. Studies frequently involve using the number of group members as an independent variable, measuring how different dependent variables change as group size increases or decreases. We’ve taken a closer look at a few of these variables below. Based on these and other variables we researched, one thing remains abundantly clear. As group size increases, no influencer of productivity and effectiveness gets consistently better (vis-à-vis making a positive contribution to the outcome of a meeting). In many cases, these variables change at exponential or near-exponential rates as more people are added to a group.
The important thing to look for when evaluating the merits of Amazon’s Two Pizza Rule is whether factors influencing productivity and effectiveness of a group—our dependent variables—increases to such a level that the variable would become severely detrimental before we reach our ten-person Pizza Rule cap.
There’s a lot of data to support the idea of a steep drop-off in productivity as group size increases. A few years ago, a group of business school professors tested a concept dubbed the “team scaling fallacy” by asking two- and four-person groups to assemble a lego figure. The two-person teams averaged a completion time of 36 minutes while the three-person teams clocked in at an average of 52 minutes. Productivity dropped almost 50% when just one extra team member was introduced.
We’ve all been in a meeting in which one person commandeers the focus, dragging the group right off the rails. It’s fair to say that derailing the group decision-making process with one’s own social quirks requires the presence of social interactions. There is some data supporting the idea that a larger group size increases the risk of sinking the productivity of a meeting and effectiveness of decision making through social interactions alone. In Amazing Applications of Probability and Statistics, author Tom Rogers found that the average number of social interactions appears to grow exponentially as group size increases.
In every group, there are a number of “links” between people. The term “links” was used, somewhat nebulously, by Organizational Psychologist J. Richard Hackman in an interview with Harvard Business Review to describe the social interconnectedness of group members (refer to the formula below). The more links between group members, the higher the risk of being hindered by the social and political detriments to optimal productivity and effectiveness. Hackman later revealed his own shorthand for determining meeting sizes, stating “my rule of thumb is no double digits”.
Image credit: https://goo.gl/1OY6KZ
A six-person group (the minimum group size fed under the Two Pizza Rule) has 15 links. The maximum group size under the Two Pizza Rule, ten people, bring the number of links up to 45. 45 is not a lot of links, but that’s to be expected when limiting group size in accordance with the Two Pizza Rule. However, the trend starts to snowball quickly. A group of 15 people has 105 links and a group of 20 has 190. Even at just ten people, there is still an average of 45 links; 45 opportunities for social and political connections to drag down the effectiveness and productivity of a meeting.
So, what did we learn here? Well, while every board has a minimum number of members needed for decision making. In reality, it’s also difficult to reduce group sizes without hurting feelings or breaking bylaws. However, the data has spoken; the smaller the better. The Two Pizza Rule is, by all indications, a fantastic shorthand for easily limiting the size of a meeting. Even on larger boards, the Two Pizza Rule can be applied to smaller committee meetings. Aim for having no more than ten people in a group. Each additional group member added beyond the ten-person cap drastically increases the various factors contributing to ineffective communication and poor productivity.
If you can’t get around meeting in a larger group, there are a number of strategies you can use to improve your productivity. Check out our article on nominal group technique to learn how larger boards can more effectively brainstorm and prioritize ideas.