I started by calling the Census Bureau. A representative called me back, without much information. “We do not define the different generations,” she told me. “The only generation we do define is Baby Boomers, and that year bracket is from 1946 to 1964.”

Next, I spoke with Tom DiPrete, a sociology professor at Columbia University. And he agreed with the Census Bureau. “I think the boundaries end up getting drawn to some extent by the media,” DiPrete said, “and the extent to which people accept them or not varies by the generation.” DiPrete explained that there was a good sociological reason for identifying the Baby Boom as a discrete generation. It “had specific characteristics,” and occurred within an observable time frame. World War II ended. You had the postwar rise in standard of living and the rise of the nuclear family. Then societal changes disrupted those patterns, and the generation, for academic purposes, was over. His main point: “History isn’t always so punctuated.”

I understood why Generation X, a generation defined by turmoil and uncertainty, would be poorly defined. But what about Millennials? Doesn’t their shared experience of the millennium transition and technology provide similar markers? “I actually haven’t seen efforts to document [generations] rigorously, and I would be somewhat skeptical that they can be documented rigorously,” DiPrete said. The things that have shaped Millennials—the rise of technology and social networks, for example—“affect people’s lives differently.”

“The media in particular wants definitions, identities,” DiPrete said. “I don’t know that the definitions are as strong or as widely shared across all the boundaries … At the end, I think it gets fuzzy.”

Well, yeah. We do want definitions. And if the media draws the boundaries, then allow us to do so definitively.

Your official demarcation of generational boundaries

We identified six different generations and labeled their eras.

Greatest Generation. These are the people who fought and died in World War II for our freedom, which we appreciate. But it’s a little over-the-top as far as names go, isn’t it? Tom Brokaw made the name up and of course everyone loved it. What, you’re going to argue with your grandfather that he isn’t in the greatest generation? The generation ended when the war ended.

Baby Boomers. This is the agreed-upon generation that falls within DiPrete’s punctuated time frame. It began when the Greatest Generation got home and started having sex with everyone; it ended when having sex with everyone was made easier with the pill.

Generation X. George Masnick, of the Harvard Joint Center for Housing Studies, puts this generation in the time frame of 1965 to 1984, in part because it’s a neat 20-year period. He also calls it the “baby bust,” mocking “pundits on Madison Avenue and in the media” who call it Generation X. Ha ha, tough luck.