As almost everyone knows, diversity is transforming day-to-day activity in the workplace. However, too much of the talk about diversity tends to focus on race, religion, and gender, while the most powerful dimension of diversity is age.

For the first time in history, there will be significant numbers of workers from four different generations in most workplaces at the same time. The differences in experiences, expectations, and objectives will create stresses. This will require managers to be more imaginative.

Let's examine the facts behind this trend and some of it implications.

Never before in the history of the American workplace have so many different age groups been found working together in such close quarters. Social demographers, the scientists who study the effects of population on society, use the term "cohort" to refer to people born in the same general time span and who share key life experiences. Members of cohorts who come of age in lean times or war years tend to think and act differently than those born and raised in peace and abundance.

Perhaps the most comprehensive analysis of managing the multi-generational work place is found in the superb book Generations at Work by Zemke, Raines and Filipczak. That book defines the four generations that work together today as follows:

1. Veterans, the 52 million Americans born between 1922 and 1943. This cohort was born before or during World War II, and their earliest experiences are associated with that world event. Some also remember the Great Depression.

2. The Baby Boomers, the 73 million people born between 1943 and 1960. These people were born during, or after, World War II and raised in an era of extreme optimism, opportunity, and progress. Boomers, for the most part, grew up in two-parent households, safe schools, job security and post-war prosperity. They represent about two-thirds of all U.S. workers. On the job, they value loyalty, respect the organizational hierarchy, and generally wait their turn for advancement.

3. Generation Xers, the 70 million people born between 1960 and 1980. They were born after the Boomers into a rapidly changing social climate and economic recession, including Asian competition. They grew up in two-career families with rising divorce rates,...