With all of this data, the team ran statistical models to understand which of the many inputs collected actually impacted team effectiveness. Using over 35 different statistical models on hundreds of variables, they sought to identify factors that:

• impacted multiple outcome metrics, both qualitative and quantitative
• surfaced for different kinds of teams across the organization
• showed consistent, robust statistical significance

The researchers found that what really mattered was less about who is on the team, and more about how the team worked together. In order of importance:

• Psychological safety: Psychological safety refers to an individual’s perception of the consequences of taking an interpersonal risk or a belief that a team is safe for risk taking in the face of being seen as ignorant, incompetent, negative, or disruptive. In a team with high psychological safety, teammates feel safe to take risks around their team members. They feel confident that no one on the team will embarrass or punish anyone else for admitting a mistake, asking a question, or offering a new idea.

• Dependability: On dependable teams, members reliably complete quality work on time (vs the opposite - shirking responsibilities).

• Structure and clarity: An individual’s understanding of job expectations, the process for fulfilling these expectations, and the consequences of one’s performance are important for team effectiveness. Goals can be set at the individual or group level, and must be specific, challenging, and attainable. Google often uses Objectives and Key Results (OKRs) to help set and communicate short and long term goals.

• Meaning: Finding a sense of purpose in either the work itself or the output is important for team effectiveness. The meaning of work is personal and can vary: financial security, supporting family, helping the team succeed, or self-expression for each individual, for example.

• Impact: The results of one’s work, the subjective judgement that your work is making a difference, is important for teams. Seeing that one’s work is contributing to the organization’s goals can help reveal impact.

The researchers also discovered which variables were not significantly connected with team effectiveness at Google:

• Colocation of teammates (sitting together in the same office)
• Consensus-driven decision making
• Extroversion of team members
• Individual performance of team members
• Workload size
• Seniority
• Team size
• Tenure

It’s important to note though that while these variables did not significantly impact team effectiveness measurements at Google, that doesn’t mean they’re not important elsewhere. For example, while team size didn’t pop in the Google analysis, there is a lot of research showing the importance of it. Many researchers have identified smaller teams - containing less than 10 members - to be more beneficial for team success than larger teams (Katzenbach & Smith, 1993; Moreland, Levine, & Wingert, 1996. Smaller teams also experience better work-life quality (Campion et al., 1993), work outcomes (Aube et al., 2011), less conflict, stronger communication, more cohesion (Moreland & Levine, 1992; Mathieu et al., 2008), and more organizational citizenship behaviors (Pearce and Herbik, 2004).