Cap decision meetings at 6-8 people — communication complexity scales as n(n-1)/2 and social cost suppresses genuine discussion beyond this

Why This Is a Rule

The number of possible conversational pairs in a meeting grows combinatorially: n(n-1)/2. A 4-person meeting has 6 pairs. A 6-person meeting has 15. An 8-person meeting has 28. A 12-person meeting has 66. As pairs multiply, several dynamics degrade simultaneously: airtime per person drops (in a 60-minute meeting with 12 people, each person averages 5 minutes of speaking), social cost of speaking increases (disagreeing in front of 12 people feels riskier than disagreeing in front of 4), and diffusion of responsibility kicks in (with 12 people, each assumes someone else will raise the important objection).

The 6-8 threshold represents the practical ceiling where meetings can still function as genuine discussions rather than presentations-with-audience. Below 8, each person has enough airtime to contribute meaningfully, the social cost of dissent is manageable, and accountability is clear (everyone's contribution is visible). Above 8, meetings tend to degrade into broadcasts where 2-3 dominant voices talk while others listen, check email, or stay silent to avoid the social cost of speaking.

Jeff Bezos's "two-pizza rule" (never have a meeting that couldn't be fed with two pizzas) targets roughly the same threshold. The constraint isn't about pizza — it's about the structural limits of multi-person dialogue.

When This Fires

• When scheduling a meeting and deciding who to invite
• When meetings feel unproductive despite having the "right people in the room"
• When meeting discussions are dominated by 2-3 voices while others stay silent
• When meetings have grown beyond their original size through invite creep

Common Failure Mode

Inclusive over-invitation: "Let's invite everyone who might have input." The intention is inclusivity; the effect is a 15-person meeting where 10 people sit silently, the discussion is shallow (social cost of depth is too high), and decisions are vague (too many stakeholders for clear commitment).

The Protocol

(1) For each meeting, identify the minimum viable attendee list: who must be present for the meeting to achieve its purpose? This is typically 3-6 people. (2) If the list exceeds 8, restructure: split into two meetings with different scopes, or designate representatives who can speak for broader groups. (3) For people who need to be informed but not participate, send meeting notes after — they don't need to attend. (4) Apply the contribution test: for each invitee beyond the core group, ask "Will this person's attendance change the meeting's outcome?" If no → don't invite. Send notes instead. (5) Monitor: if a meeting regularly has participants who never speak, they probably don't need to be there. Remove them from the invite and share notes instead.