Amazon's two-pizza rule: no meeting should be so large that it can't be fed with two pizzas. It's a rule about meeting size, but it's really a rule about effectiveness.
Why Meeting Size Matters
Every person you add to a meeting reduces its effectiveness by about 10%. More people means more communication overhead, more tangents, more passive participants.
I've seen this play out repeatedly. A 5-person meeting produces decisions. A 15-person meeting produces discussion. The larger the meeting, the less likely anything gets decided.
The Math of Meeting Size
Studies show that each additional person in a meeting:
- Reduces individual participation by ~15%
- Increases the likelihood of social loafing (someone doing nothing)
- Extends meeting duration by ~10% per person
- Decreases decision quality after a certain threshold
The sweet spot is 4-7 people. Enough to get diverse perspectives. Few enough that everyone participates.
How to Apply the Two-Pizza Rule
Invite only decision-makers. Not people who need to be informed — they'll get the memo after.
The owner attends. The person most affected by the decision should be there.
Bring in experts selectively. If you need specific expertise, bring that person for that topic only.
Consider "player plus coach." One person makes the decision, one person facilitates. Everyone else is optional.
What to Do With Large Meetings
If a meeting is too large, split it. One meeting to gather input, one to make decisions. Or use async methods to gather input before a smaller synchronous meeting.
Large meetings rarely produce decisions. They produce committees.
The System Behind It
I use a Meeting Mastery System that helps teams right-size their meetings:
- Pre-meeting checklist for attendee justification
- Decision-first meeting structure
- Time-boxed agendas
- Action trackers
The two-pizza rule isn't about pizza. It's about keeping meetings small enough to work.
[Link to Meeting Mastery System in bio]
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