Yes — the research is consistent on this. Harvard Business Review research establishes that meetings with eight or more attendees are at significantly higher risk of being ineffective. Fellow’s data shows that 35% of employees themselves identify smaller attendee lists as the strongest predictor of meeting success. The cognitive mechanism is well-documented: as group size increases, individual accountability for contribution and decision-making diffuses, dominant voices crowd out broader participation, and the time required to achieve genuine consensus increases non-linearly. The optimal meeting size for decision-making is 4–6 people; for collaborative problem-solving, 3–5.