What happens when you add someone to a high-performing team?
Bruce Tuckman published his model of group development in 1965: Forming, Storming, Norming, Performing. Sixty years of replication have kept the core finding intact. The stages aren’t a rigid ladder. Teams can regress, but the developmental work doesn’t disappear. Add or remove a single member and the clock resets.
Now count how many times your organization has reorganized product teams in the last 18 months.
The Stages, Compressed
Forming. Politeness. People figure out roles, norms, and who knows what. Velocity is low. Nobody admits confusion.
Storming. Conflict. Different working styles collide. The team’s actual hierarchy emerges, which rarely matches the org chart.
Norming. Cohesion. The team settles into a rhythm. Standards emerge. Trust builds. Velocity climbs.
Performing. Flow. The team operates with minimal friction. Decisions happen without escalation. Work ships predictably.
The time from Forming to Performing varies. It’s never zero. A team stable for six months might move from Storming to Norming in weeks. A team assembled from four different squads with a new tech lead might spend months in Storming.
Why This Destroys Roadmaps
When leadership adds three engineers to “accelerate delivery,” they’re applying a resource model: more people equals more output. Under Tuckman’s model, more people equals a reset to Forming, followed by Storming that actively reduces output below the pre-expansion baseline.
The team that was shipping predictably becomes a team that’s learning to ship together. Existing members adjust. New members learn the codebase, the domain, the stakeholders. For weeks, sometimes months, the team is slower than before the expansion.
In effect, Brooks’ Law is a special case of Tuckman.
What to Do Instead
You can’t avoid churn. People leave. Headcount arrives. Reorgs happen. But you can account for the reset:
Budget a Norming sprint. When a team changes composition, the next sprint’s goal should be conservative. Not because the new people aren’t good. Because the team doesn’t exist yet.
Don’t measure the new team against the old team’s velocity. The baseline is invalid. Track the new team’s trajectory instead.
Assign an explicit Norming facilitator. Someone (the PM, the tech lead, an EM) should explicitly own the transition. Not “the team will gel.” Someone whose job is to accelerate trust and clarity.
Why Stuck Teams Stay Stuck
The people brought in to fix a stuck team are usually entering at Storming. A program that is behind, or a transformation nobody asked for, follows the same shape: move the team from Storming through Norming to Performing, then the next problem starts the cycle again.
The pattern isn’t accidental. Leadership doesn’t put its best people on stable teams. It puts them on the ones that are stuck.
The Agent Angle
When AI agents join a team, Tuckman still applies. Forming now includes agents learning the team’s conventions and the team learning the agents’ failure modes. Humans trust agents too much at first or too little. The Norming phase (calibrated trust) takes deliberate work.
If your org has reorganized in the last 12 months and your roadmap treats the new teams like the old teams, your timeline is fiction. Budget the Forming-to-Storming tax before the dates slip. s@spencervaradi.com.
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