Thriving Teams #8: Team Diversity

In the build up to the 9/11 attack on New York City, the CIA missed countless clues that may have lead to the detection of the plans to destroy the World Trade Centre. The organisation suffered from perspective blindness, the way in which we can be ignorant to our own blind spots; the Agency had created homogenous teams of mainly white, middle class, similarly educated staff. They were intelligent, shrewd, and completely lacking in cultural or cognitive diversity to tackle wide-ranging problems. Put simply, a more diverse group would have had a richer understanding not just into the threat posed by al-Qaeda, but other dangers in the world. This is what Matthew Syed contests in Rebel Ideas when talking about the CIA and its staff: ‘each would have been assets in a more diverse team. As a group, however, they were flawed.’

Syed isn’t taking particular aim at the CIA, but rather the way that many organisations have, and continue to, staff their teams. Rebel Ideas, which I draw upon further in this post, contains many lessons about creating diverse teams that will improve team performance.

According to research from Forbes (2017), teams outperform individual decision makers 66% of the time, and decision making improves as team diversity increases. Compared to individual decision makers, all-male teams make better business decisions 58% of the time, while gender diverse teams do so 73% of the time. Teams that also include a wide range of ages and different geographic locations make better business decisions 87% of the time. This is only one piece of research, and, honestly, there are other studies that show that greater diversity can cause other barriers to thriving team work, but one thing is for sure, we have a lot to learn about team diversity.

What diverse teams are and why they matter:

Team diversity can encompass both inherent (e.g., race, gender) and acquired (experience, education, cultural background) differences among the team’s members.  Some of these differences are more obvious than others. For example, we can visually observe a team’s racial or gender diversity, and there are studies that show the reduced effectiveness of those groups who lack diversity in these areas. It can be more difficult to understand the team’s diversity in their acquired features; for example, two team members with similar inherent characteristics, may have a diverse breadth of experience between them that is only apparent upon further investigation. Conversely, two members who are inherently different (i.e., visually diverse), may share similar expertise, views and experiences. So there is a nuance about what kind of diversity will truly serve the team.

Matthew Syed distinguishes diversity as cultural diversity (race, sex) and cognitive diversity (their experience, skills, ways of solving problems). He suggests in Rebel Ideas (Syed, 2019) that cognitive diversity is the most potent for teams, suggesting that it doesn’t matter where team members are from or what age they are, if they are all trained in the same discipline, they won’t naturally bring a wide array of viewpoints to a discussion.

Complex problems generally rely on multiple layers of perspectives. The more diverse the team, the larger range of potentially viable options there are. Whilst we all have our own ‘blind-spots’ which we cannot see, as noted in the CIA, we can lean onto others to help make us aware of them. As Syed writes, if you have 10 of the best minds who all think alike, then the ideas brought to the table are effectively just one person’s worth. However, if you have 10 minds all thinking differently, then there is no limit on the amount of creative and inventive ideas that will emerge.

While it is arguable that organisations are becoming more alert to the benefits of diversity, there is still a long way to go. In the latest issue of the Harvard Business Review (sign posted by D Clutterbuck), a study found, based on board meeting transcripts, that, while each white male spoke for an average of 11% of the time, women averaged only 8% and black directors a mere 4% (HBR, 2022).  This reveals that there is a long way to go in creating equity in organisational culture, and this post will highlight how team diversity isn’t just about initial recruitment, but rather a team’s culture and promotion of diverse views and thinking in its teams and boardrooms.

And, what are they waiting for? A 2015 McKinsey report on 366 companies found that those in the top quartile for ethnic and racial diversity in management were 35% more likely to have financial returns above their industry mean, and those in the top quartile for gender diversity were 15% more likely to have returns above (HBR, 2015). Many more studies come to the conclusion that non-homogenous teams are simply better at working together; diversity in teams challenges members to think beyond their own perspective, and to become more objective, interrogative, and innovative.

In a study by the Journal of Personality and Social Psychology, and supported since by others, when juries were populated by diverse groups, they were less likely to make factual errors than homogenous groups. In a separate financial study, researchers found that individuals who were part of the diverse teams were 58% more likely to price stocks correctly, whereas those in homogenous groups were more prone to pricing errors.

Diverse teams are found to be more likely to re-examine information, to debate different points of view, to scrutinise each other’s actions, and most importantly, disrupt homogeneity and the groupthink mindset where we revel in the comfort that our team members are similar to us, and will likely agree with our line of thinking. Finally, studies also reveal that diverse teams are more likely to be innovative, and develop new products.

Before we look at challenges that diverse teams face, let me summarise that team diversity can allude to cultural or inherent characteristics, cognitive characteristics, and also the culture of the team to contribute new and diverse ideas. The post isn’t advocating for certain methods of recruitment or to make tokenistic gestures towards diversity, but rather aims to highlight the huge benefits that teams can enjoy when they have a group that brings differing experiences, skills, views, and culture.

Some challenges:

However, while there is plenty of research to laud the effects of team diversity, there are challenges to consider when staffing teams.

Teams can develop what are known as a ‘fault lines’ (Bell & Brown, 2015)– divisions that may compromise team cohesion, relationships, and effectiveness. In other words, the team may form subgroups, based on one or more attributes; these faultlines are their strongest (and worst) when they are across several attributes, e.g. profession, sex, education all at once. Teams with fault lines are more likely to split into subgroups or cliques, leading to increases in task and relationship conflict, and decreased team cohesion. Knowing that these faultlines exist is important, not from the perspective of recruitment (for many reasons!) but in terms of how we utilise team diversity as a benefit and not a hindrance. More on that later.  

Sticking with what you know, or creating an echo chamber, can feel pretty good. Regular affirmation regarding your approach feels pleasant. A sense of collegiality and everyone rowing in the same direction is enthusing. But these subjective feelings mask what is likely to be an inefficient team.  Our unconscious bias, studies show, means that we tend to think pessimistically about diverse teams and viewpoints, even when the benefits are occurring in front of us. We tend to revert to the comfort of homogeneity.

One study (HBR, 2016) involved participants solving a murder mystery; during the process, teams were joined by new members, with some groups adding a member from their existing network, and others receiving someone unknown to them – an outsider. Interestingly, the teams with new members who were known to them felt more confident about the process and their final decision; teams joined by an ‘outsider’ judged their interactions less effective, and were less confident about their outcome. And yet, those latter teams’ success rates were 60%, compared to the 29% of more homogenous teams. Research shows that this isn’t uncommon: so the onus is on the team and its leaders to normalise diversity, celebrate it, and acknowledge what the team needs to in order to successfully navigate a range of views and opinions.

Working on diverse teams with a variety of viewpoints and experiences can feel like hard work, because it is. It is more complex and nuanced to navigate a discussion of differing ideas, examining facts carefully and finding a path forward as a group. It feels harder, and yet it produces results. Psychologists call our desire for easier processes the fluency heuristic – just like re-reading material can seem like a simple, effective way to consolidate learning (warning, do not do this!), we may feel positively about a group discussion with low conflict and high agreement.

Interestingly, studies have shown that people overestimate how much conflict there is in diverse teams. This type of unconscious bias can clearly have a significant impact not only on hiring but also on the ways in which leaders create teams and encourage collaboration.  Without realising it, they may be reluctant to add diversity to a team or to assign colleagues with different backgrounds to work together, in response to fear of the tension and difficulty that could ensue.

Put simply, we like group think, which is the term attributed to the phenomenon of homogenous team thinking. Irving Janis stated (Yetiv, 2003) that striving for unanimity overrides motivation to realistically appraise alternative courses of action. As Janis points out, when ‘groupthink dominates, suppression of deviant thoughts takes the form of each person’s deciding that his misgivings are not relevant, that the benefit of any doubt should be given to the group consensus.’ As a result, individuals hesitate to dissent, and conflict avoidance becomes a norm. Groupthink is most likely to occur in groups that are cohesive or, in other words, exhibit a high level of amiability among their members 

In task-oriented work teams, there is some evidence that team members have more social affinity toward one another when they are similar; however, social affinity does not necessarily indicate which team members will rely on one another for expertise or team efficacy (Joshi, 2015). In other words, superficial affinity can feel comforting, but it doesn’t have as much impact on team performance as the team’s ability to work together.

Ways to boost team diversity and effectiveness:

So far, we’ve discussed both the proven benefits of team diversity, as well as exploring some challenges that diverse teams may face before they see the fruits of their labours. So, how can teams really harness the power of being different?

  1. Highlighting differences and group identity: there is a huge body of evidence that supports creating an agreed vision, purpose, and sense of belonging in a team. Unsurprisingly, research says the same about group differences. If the group’s identity is built on the acknowledgement and celebration of its diversity, the team are more likely to accept and benefit from these differences. In other words, fault lines can be reduced by positively framing the team; groups perform better when they believe in pro-diversity, and this needs to be narrated and verbalised by leaders.
  2. Goals: nothing unites a group and gives it compelling direction like a set of agreed goals. These should be specific, team goals, which will bind the team together and help them focus on the bigger picture, even if some of their differences do feel difficult at times.
  3. Improving team cohesion and helping behaviours:  Liang et al (2014) found that team diversity can lead to lower levels of helping behaviours among teams, and therefore it is important for teams and their leaders to devote time to developing a sense of team unity and cohesion, perhaps through a shared identity, or more practically through clearly defined roles and understanding of the team’s expertise and processes. If the team has role clarity, and understanding of different aspects of its expertise, they can appreciate each other’s contributions.
  4. Reject hierarchy: In Rebel Ideas, Matthew Syed quotes a study from 1972 that discovered that teams lead by junior managers were more likely to succeed than those with a senior manager in charge. Confusingly, studies also show that teams with no managers at all don’t perform that well. Syed discusses the ‘prestigious’ leader. These are individuals who attain influence and command without engaging in displays of dominance. Individuals who exhibit prestige share wisdom and are willing to teach others. They recognize they don’t know everything, so they instead listen attentively to others when they need to.  It is this form of transformational leadership that is most likely to facilitate the benefits of a diverse team.
  5. Psychological Safety: if a team is diverse, inherently or cognitively, that may mean little to its chance of progress if there is no culture of psychological safety. Psychologically safe teams are open to discuss processes, successes and failures; there is a culture of healthy feedback and an absence of blame. Given that a diverse team may feel less naturally comfortable in this environment than a homogenous group, efforts should be expended to build belonging and psychological safety. The benefits of the diverse thinking of the team will be lost if individuals don’t feel confident in contributing to team discussions.
  6. Mix it up to innovate: For teams to achieve innovation in the workplace, diversity can be a key component. Syed points out that academic papers with the “most impact” were found to have “atypical subject combinations” whereby academics bridged traditional boundaries and married two topics together – like physics and computation or anthropology and network theory. By inviting, yes – actually seeking out, diverse opinions, views, and expertise, the team can look beyond its assumed positions, and see existing processes with fresh perspectives.

How can we apply these lessons to schools?

School teams present many challenges and opportunities. Most teams, let’s say tutor teams in a secondary setting, won’t have been put together deliberately based on an optimal combination of cultural or cognitive diversity. And yet, they will be diverse and teeming with experience and views.

School staff are often part of multiple teams, some of which they will have chosen, and others not. Some they will have been recruited deliberately for, and others not. This dynamic presents challenges in that we often cannot compose a team based on a variety of attributes. So, what can we do to maximise diversity?

School teams should be hives of psychological safety and belonging. Using some of the strategies from earlier in this blog post, leaders should normalise a team culture where members not only feel safe to share and learn together, but also build in time and opportunities for the culture to grow. Meetings and debriefs can be scheduled to discuss ideas and processes; members can be given ownership over leading team learning in meetings. Finally, leaders should verbalise the uniqueness and strength of the team’s diversity, and create a culture where every member understands the benefits of their differences.

It’s clear from research that, while diverse teams can be difficult to create and, in some cases, manage, the benefits are potentially fantastic. There are many layers, from an ethical principle of inclusion, equality, and diversity, to the sheer potential that diverse teams have to significantly outperform homogenous groups. I hope that this post has helped your own thinking about the creation and success of your teams.

Thank you for reading



Bell, S.T. and Brown, S.G. (2015), “Selecting and Composing Cohesive Teams”, Team Cohesion: Advances in Psychological Theory, Methods and Practice (Research on Managing Groups and Teams, Vol. 17), Emerald Group Publishing Limited, Bingley, pp. 181-209.

Forbes (2017) New Research: Diversity + Inclusion = Better Decision Making At Work. New Research: Diversity + Inclusion = Better Decision Making At Work (

Harvard Business Review (2015) Why Diverse Teams Are Smarter (

Harvard Business Review (2016) Diverse Teams Feel Less Comfortable — and That’s Why They Perform Better

Harvard Business Review (2022) A seat the table is not enough, pp21-25

Joshi, A., & Knight, A. P. (2015). Who defers to whom and why? Dual pathways linking demographic differences and dyadic deference to team effectiveness. Academy of Management Journal, 58, 59 – 84

Hsiao-Yun Liang, Hsi-An Shih, Yun-Haw Chiang (2014) Team diversity and team helping behavior: The mediating roles of team cooperation and team cohesion, European Management Journal,Volume 33, Issue 1,

Syed, M (2019) Rebel Ideas

Yetiv, S (2003) Group Think. British Journal of Political Science , Jul., 2003, Vol. 33, No. 3 (Jul., 2003), pp. 419-442

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