Here’s the most important story for human resources that has come along in quite a while. It comes from the National Academies of Science, Engineering and Medicine, the independent research organization that undertakes policy-focused research for the U.S. government and its agencies.

This particular study was undertaken for the U.S. Army, which recruits about 80,000 new soldiers every year and has an interest in whether young people are really different now than in the past. The question they asked the National Academies to investigate was to what extent is thinking about generational differences useful. An outside committee of experts prepared the report after poring over all the evidence and hearing from other experts and interested parties.

The report they issued is called, appropriately enough, Are Generational Categories Meaningful Distinctions for Workforce Management? These reports usually produce a lot of “on the one hand” and “on the other hand” conclusions. Not so in this case. Here’s their conclusion: “A focus on generational characteristics is not supported by science and is not useful for informing workforce management decisions.”

Allow me to translate: There is nothing sensible or useful in the idea of “millennials” or “Gen X” or “four generations in the workforce” or “Gen Now” (OK, I made that one up). Nada. Zip. Nothing. It’s all made up. No demographers ever made these claims about generations in the first place. It was consultants. The story kept getting repeated, and now it is one of those “touchstones” that many people just assume.

If younger employees are job hoppers, it is not because they are from a different “generation.” They are just younger, and younger people have always changed jobs more frequently. Yes, they do everything on their cell phones now. That’s because we could not do everything on cell phones when we were their age.

If you are skeptical of my interpretation of this study, read it yourself.

If it was true, say, that “millennials” were a real generation, what would that mean? It is only that they have values on average that are different at the same age from those born before and those born after. It does not mean that everyone in that cohort has identical values or that those values are particularly distinct. If you are hiring 100 people out of an age group of 10 million, just find the 100 who fit what you want. Thinking about all of them as all having identical values would be absurd in any case.

If you wanted to see if there really are generational differences, you wouldn’t compare 25-year-olds to 50-year-olds. You would compare 25-year-olds today to those who were 25 a decade ago. When the National Academy committee did that, they found no real differences. Young people today are more or less the same in their fundamental values and interests to those of the same age all the way back to the baby boomers, which is the last, clear generation.

Read more from columnist Peter Cappelli HERE.

The generational claim is that those attitudes and values that they have now will persist. But if we actually adapted the workplace to young people, we would just irritate them when they are older: They don’t care that much about health insurance and retirement accounts, but I guarantee they will when they hit 55.

OK, a generation advocate might say, so this is really just about age differences. They are useful labels. It’s not a useful label, and the reason is because we will age out of those categories. We think about millennials as young people, for example, but they are already age 40 at the upper end. For the purpose of managing them, is there really a lot in common between 40-year-olds and 24-year-olds, which is the age range claimed for millennials? Virtually no millennials are new entrants to the workplace, yet we seem to describe them that way.

It seems to me that we never really did anything with these generational claims other than produce reports and hold seminars to tell managers how to relate to them, which the managers quickly ignored. What these claims did do, however, is waste time and energy in already stretched human resource departments.

Related: Here’s why millennials aren’t that different

So here is my question: How did it happen that something for which there never was any evidence became an article of faith in the HR community? A partial explanation is that the demographers didn’t bother to try to shoot it down because most of them are not interested in what is going on in business, but that does not explain why it caught on.

Here’s the second question: I strongly suspect that this report will make no difference, that we will still be talking about how to appeal to millennials and the challenge of having all these generations in the workplace at the same time. Why is it that evidence doesn’t matter?