From the American Management Association (AMA):
“A mixture of genders, ethnic backgrounds, and ages in senior management consistently correlates to superior corporate performance, according to an American Management Association survey performed in partnership with Business and Professional Women USA. . . .
“While larger companies were more likely to include at least one senior manager who is female, or under 40, or of non-European descent, smaller firms had a greater percentage of such individuals at the top table, and a greater likelihood that a majority of the senior managers were outside the white, male, over-40 model. Smaller firms were also far more likely to include a high percentage of relative newcomers (i.e., with the organization less than five years) among their senior executives. While small-company growth rates are often higher than those of larger firms, the survey data shows that within organizations of similar size, such factors as heterogeneity, open teams, and a hefty flavoring of youth still correlate strongly to better results. . . .
“Women hold a greater percentage of senior management posts in service firms (average: 17.8 percent) than in manufacturing companies (average: 12.9 percent). Women particularly predominate in such sectors as communications (average: 31.6 percent), and business and professional services, which includes software developers and business consultancies (average: 31.4 percent), and have greater-than-average representation on senior management teams in finance, insurance, and real estate. These are the same business sectors that outperformed the manufacturing sector in every category of organizational performance listed in the AMA questionnaire. Again, correlation is not causation, but women have certainly seized the opportunities for advancement offered in the service sector, and have prospered with that sector.
“Persons of African, Latin, and Indo-European descent have a higher degree of representation on senior management teams in smaller companies and in the service sector, which again tend to report better organizational outcomes than larger companies and manufacturers. . . .
“In the wider view, it is not the predominance of any one set but rather the participation of managers of varying gender, ethnicity, age, and experience that correlates to strong organizational performance. Where sub-sets are large enough to provide statistical reliability, the presence of ’some’ such managers on the senior management teams generally correlates to better performance than does an indicated presence of ‘none.’”