notes · research summary

Project Aristotle: what makes teams effective?

A few years after Project Oxygen (which I covered in the previous note), Google ran an internal study called Project Aristotle to answer a big question: what actually makes a team successful? The result, drawn from hundreds of teams, was clear — the most effective teams are not necessarily the ones with the smartest or most experienced people. They are the teams that interact well, keep healthy human connections, and grow in an atmosphere of psychological safety.

1. Psychological safety

The single most important factor. Team members can freely share opinions, make mistakes, ask questions, and voice raw ideas — without fear of judgement, ridicule, or punishment.

Amy Edmondson, who introduced the concept, notes it is not the same as "group cohesion". Psychological safety means that even when there is disagreement, members feel they can respectfully object and still remain part of the team. In such an environment people stop performing roles and bring their real selves to meetings — which is what unlocks learning, collaboration, and accountability.

Managers are the facilitators of this space:

• Respond supportively to mistakes; replace blame with curiosity.
• Enable open, respectful dialogue even during conflict.
• Keep communication simple, warm, and understandable.
• Ask the team for continuous feedback — and visibly act on it.

2. Dependability

A team works well when members can count on each other: tasks delivered on time, quality that holds up, promises kept. Dependability shows up in small behaviours — arriving at the meeting on time, replying clearly to a short email — each one a signal that either strengthens or erodes trust.

The manager's role here:

• Model commitment and accountability personally.
• Define roles and expectations precisely and transparently.
• Keep channels open so people can raise problems without fear.
• Give constructive feedback people can actually grow from.

3. Structure and clarity

The best teams know exactly what they must do, why they do it, and how their success is measured. Tools like OKRs and the RACI matrix help teams align goals with the organisation, divide work properly, and make it explicit who is responsible, who is accountable, and who just needs to stay informed. In remote and hybrid work, this clarity matters more than ever.

4. Meaning

Members must feel their work means something and is part of something bigger. For one person meaning lives in learning; for another, in impact, or in supporting their family. When people find meaning in the work, they are more motivated, more creative, and more committed. A simple project can become a mission — if the person knows why it matters.

Ways to strengthen meaning in a team:

• Continuous positive feedback and recognition.
• Connecting each person's work to team or organisational goals.
• Sharing how the work finally touches customers or users.
• Helping each member build their own career story.

5. Impact

When members see that their output genuinely makes a difference — for the team, the organisation, or the customer — motivation rises. Impact means: my effort is visible, and it matters.

The gTeams practice

To put the findings to work, Google built the gTeams exercise: teams run a ten-minute survey on the five factors, then hold a session to discuss results and design improvements. Teams that practised it regularly — starting meetings with a short, friendly check-in, for example — saw roughly 6% growth in psychological safety and about 10% in clarity of roles and plans. The tool was designed for Google, but the principle applies to any team: a simple measurement, an honest conversation, and a commitment to keep improving.

This note is connected to my Persian translation of Leading Effective Engineering Teams by Addy Osmani — the book and translation live here. If you haven't yet, read the Project Oxygen note — it is the story of how Google first proved that managers matter.