You hear about Millennials, Generation X, and the Baby Boomers all the time, but it’s not always clear who’s a part of these groups. In fact, all of these terms are fairly unofficial social constructs outside of the Boomers—the U.S. Census [PDF] actually defines them as the generation of people born between 1946 and 1964. Now, the Pew Research Center is looking to give more structure to these generational nicknames with a new set of guidelines that establishes where each person belongs depending on their birth year. This is what they’ve come up with:

The Silent Generation: Born 1928-1945 (73-90 years old)

Born 1928-1945 (73-90 years old) Baby Boomers: Born 1946-1964 (54-72 years old)

Born 1946-1964 (54-72 years old) Generation X: Born 1965-1980 (38-53 years old)

Born 1965-1980 (38-53 years old) Millennials: Born 1981-1996 (22-37 years old)

Born 1981-1996 (22-37 years old) Post-Millennials: Born 1997-Present (0-21 years old)

In addition to defining the birth years of Boomers and Gen-X'ers, Pew’s main focus with this research was to highlight where Millennials end and the yet-unnamed “Post-Millennial” generation begins. The new Millennial cutoff of 1996 is important because it points to a generation that is old enough to have experienced and comprehend 9/11, while also finding their way through the 2008 recession as young adults.

Those born between 1981 and 1996 will have been affected by the economic downturn in numerous ways: some would have had their early careers impacted, while others would have had their education influenced by it (perhaps through prohibitive tuition costs or a change in major to find a field with jobs). President of the Pew Research Center Michael Dimock said the recession’s effect on Millennials and the initial “slow start” to their careers “will be a factor in American society for decades.”

Technology also plays a factor in the dividing lines between generations. The study gives an example that the oldest “Post-Millennial” members would have been 10 when the iPhone was introduced, whereas many Millennials will still have memories of landlines, touch-tones, and rotary phones. As technology plays a more encompassing role in our lives, these societal developments are seen as a big enough distinction to draw generational lines through. Dimock points to Baby Boomers as a generation that saw TV become dominant, Generation X experienced a computer revolution, and Millennials grew up in an age where the internet became a new way of life.

Pew's new guidelines do alter a few others that came before. Some have put the Millennial generation from 1982-2004 (easily making it the longest generation), while others would have wanted to end it in the early '90s.

In establishing these guidelines, it also looks like the “Xennial” has been wiped from existence. This is a micro-generation that encompassed those born between 1977 and 1983—they identified themselves as people who grew up in a pre-digital world and later adapted to today’s technology. If this includes you, you’re now either a late-term Gen X’er or a grizzled veteran of the Millennial clan.

Dimock himself makes it clear that these “cutoff points aren’t an exact science.” They're simply tools to analyze the different shifts in how age groups are experiencing the world—socially, economically, politically, and technologically.