Opinion: What’s the two-pizza team-size rule?

Until 1913, conventional wisdom suggested that the problem of calculating total work done is an algebraic one; a single human bricklayer can typically lay on average 400 bricks per day, so if ten were employed, you could expect 4000 plus bricks daily. 

Group effort and team participation were assumed to lead to increased effort on behalf of the members reliably, so larger groups could increase overall productivity to even 5000 bricks. We've been consistently told even today that a team of people could complete working more efficiently than individuals working separately through processes such as synergy and collaboration.

It was only until a French agriculturalist named Max Ringelmann published a report called ‘research on animated engines, human work’, in which he put forth an opposing view at the time, did the industry get clarity on group performance. He proved this with a simple rope-pulling experiment that showed that each individual when added to the group, the resultant force applied by each individual (measured by a dynamometer) was reduced.

For example, if one worker’s total force was 1.00, the force exerted by two through eight employees was 1.86, 2.55, 3.08, 3.50, 3.78, 3.92, and 3.92, demonstrating a curvilinear relationship between group size and group performance. See the chart above.

Ringelmann said, “It is the tendency for individual members of a group to become increasingly less productive as their group size increases. He discovered that as more people are added to the group, it becomes increasingly inefficient. It is called the Ringelmann effect or social loafing.”

And it doesn’t just happen in rope-pulling games: It’s present in companies like Amazon, Google and Facebook more than a century after Ringelmann’s discovery. And chances are, it’s happening in your workplace, too.

Group productivity = Potential productivity – Motivational losses – Coordination losses

Ringelmann said that a group fails to achieve its maximum potential because of two key reasons: 

• Motivational losses: Individuals tend to loaf about more, assuming their teammates will pick up the slack. Or that their effort doesn’t count or a lack of motivation
• Coordination losses: The cost of coordination and communication grows as the team grows. Look at this formula for how links grow to accelerate as the team size increases. 

The number of links = N(N-1)/2 (N = Number of people); Simply put, each additional person will increase the total productivity of the team but at a decreasing rate, which means if you were the fourth member to join a team, you made a more significant impact on its productivity than if you were the tenth.

So, what can organisations do to overcome this effect? Here are some solutions: 

Two-Pizza team size rule

In the early days of Amazon, Jeff Bezos instituted a rule: every internal team should be small enough to be fed with two pizzas. The higher the interdependence of tasks and the need for team collaboration, the more likely a smaller team will perform better. Small groups of sizes 4-6 are often more cohesive than large groups who find maintaining the same close relationships difficult. 

Increase identifiability

People are more motivated to put more effort into collective work when they believe their thoughts or outputs are recognisable. If a team task allows members to remain anonymous, they would feel less pressured about being judged by others, resulting in social loafing and lower productivity on the group task. 

Use the right communication tools

Use tools and processes that lower coordination costs and save time. This may mean finding friendlier collaboration apps or changing how you participate in and run meetings.

Bound by purpose

One needs to give the team something to care about more than themselves. It helps explain how the team is unique and why what they do is essential to the business. It generates a sense of urgency and fulfilment.

Over-communicate clarity

It’s all about communicating business priorities, action plans, behaviours, roles and responsibilities and what success looks like over and over again without losing the meaning. The average employee will not believe a leader’s message until they’ve heard it seven times. Employees must hear the key message repeatedly for it to be ingrained in their minds as truth. It’s all about embedding clarity into the fabric of your team.

Balance and bring clarity to roles

A well-functioning team has rhythm and energy because everyone knows their roles and responsibilities. It’s a natural buzz of energy, engagement, and potential, similar to rowing team members. You can’t always see it, but you know the power exists. 

This paper throws light from a mathematical standpoint on ‘group effects on productivity’ from the works of Ringelmann and Steiner. Group productivity is more complex to measure in the real world as the tasks are not easily addictive and will vary by task type and group experience. The article, however, aims to delve into the priority reasons that need optimising. 

(The author is the country service line leader, innovation, Ipsos India)