Team activities require a variety of skills and knowledge. Given this requirement, it would be reasonable to conclude that heterogeneous teams those composed of dissimilar individuals would be more likely to have diverse abilities and information and should be more effective. Research studies generally substantiate this conclusion, especially on cognitive, creativity demanding tasks.

When a team is diverse in terms of personality, gender, age, education, functional specialization, and experience, there is an increased probability that the team will possess the needed characteristics to complete its tasks effectively. The team may be more conflict-laden and less expedient as varied positions are introduced and assimilated, but the evidence generally supports the conclusion that heterogeneous teams perform more effectively than do those that are homogeneous. Essentially diversity promotes conflict, which stimulates creativity, which leads to improved decision making.

But what about diversity created by racial or national differences? The evidence indicates that these elements of diversity interfere with team processes, at least in the short term. Cultural diversity seems to be an asset for tasks that call for a variety of viewpoints. But culturally heterogeneous teams have more difficulty in learning to work with each other and in solving problems. The good news is that these difficulties seem to dissipate with time.

In the newly formed culturally diverse teams under perform and in the newly formed culturally homogeneous teams, the differences disappear after about three months. The reasons are that it takes culturally diverse teams while to learn how to work through disagreements and different approaches to solving problems.

An offshoot of the diversity issue has received a great deal of attention by group and team researchers. This is the degree to which members of a group share a common demographic attribute, such as age, sex, race, educational level, or length of service in the organization, and the impact of this attribute on turnover. We call this variable group demography.

Here we consider the same type of factors, but in a group context. That is, it’s not whether a person is male or female has been employed with the organization for a year rather than 10 years that concerns us now, but rather the individual’s attribute in relationship to the attributes of other s with whom he or she works. Let’s work through the logic of group demography, review the evidence, and then consider the implications.

Groups, teams, and organizations are composed of cohorts, which we define as individuals who hold a common attribute. For instance, everyone born in 1960 is of the same age. This means they also have shared common experiences. People born in 1970 experienced the information revolution, but not the Korean conflict, and people born around 1920-30 shared India’s independence struggle. Women in Indian organizations today who were born before 1945 and similarly, those when after 1970 have different experiences from women born after 1960.

Group demography, therefore, suggests that attributes such as age or the date that someone joins a specific work team or organization should help us to predict turnover.

Turnover will be greater among those with dissimilar experiences because communication is more difficult. Conflict and power struggles are more likely and more severe when they occur. The increased conflict makes group membership less attractive, so employees are more likely to quit. Similarly, the losers in a power struggle are more apt to leave voluntarily or to be forced out.

A number of studies have sought to test this thesis, and the evidence is quite encouraging. For example, in departments or separate work groups in which a large portion of members entered at the same time, there is considerably more turnover among those outside this cohort. Also, when there are large gaps between cohorts, turnover is higher.

People, who enter a group or an organization together, or at approximately the same time, are more likely to associate with one another, have a similar perspective on the group or organization, and thus be more likely to stay. On the other hand, discontinuities or bulges in the group’s date of entry distributions are likely to result in higher turnover rate within that group.

The implication of this line of inquiry is that the composition of a team may be an important predictor of turnover. Differences per se may predict turnover. But large differences within a single team will lead to turnover. If everyone is moderately dissimilar from everyone else in a team, the feelings of being an outsider are reduced. So, it’s the degree of dispersion on an attribute, rather than the level, that matters most.