Someone - specifically the father-daughter team of Larry and Meagan Johnson of Phoenix, Arizona - has figured out that on some American job sites, five generations are working side by side.
And while such an age disparity adds a lot of texture and an assortment of life experiences, it can also bring tensions and conflicts.
The Johnsons are human-resource trainers and public speakers. Dad Larry is a former health-care executive; daughter Meagan is a onetime corporate saleswoman.
Here are the oldest and youngest of the five generations they identify:
They call the oldest group Traditionals, born before 1945. They were heavily influenced by the stern lessons of the Great Depression and World War Two. They respect authority, set a high standard of workmanship, and communicate easily and confidently. But they're also stubbornly independent. They want their opinions heard.
At the other extreme are what the Johnsons call Linksters, born after 1995 into today's more chaotic, media-saturated world. They live and breathe technology and are often social activists.
You won't find many 15 year olds in corporate offices except as interns, of course, but quite old and quite young workers do come together in retail environments like bike shops and ice-cream stands.
The Johnsons' point is that as the average lifespan continues to rise and retirement dates get postponed because of the tight economy, people of different generations are working side by side, bringing with them very different ideas about company loyalty and work ethic.
The five generations are heavily influenced by quite-different events, social trends, and cultural phenomena of their times. Their experiences shape their behavior and make it difficult, sometimes, for managers to achieve a cohesive mission at the workplace.
Larry and Meagan Johnson discuss all this in greater detail in a new book, "Generations, Inc.: From Boomers to Linksters -- Managing the Friction Between Generations at Work," published by Amacom Press.
