The Harvard Institute of Politics’ latest poll of the Millennial generation, Americans between ages 18 and 29, provides further information on an interesting and potentially important Generation Gap. Not the Generation Gap between Millennials and their elders — Millennials voted 60 percent to 37 percent for President Obama in 2012, while their elders (extrapolating from the exit poll) voted 49.3 percent to 48.8 percent for Mitt Romney — but between younger Millennials (18-24) and older Millennials (25-29). In the 2012 election, there was no significant difference between them: Older Millennials voted 60 percent to 38 percent for Obama, younger Millennials 60 percent to 36 percent.

But the Harvard IOP poll shows Obama approval among older Millennials at 48 percent and among younger Millennials at 45 percent. That’s in line with differences between the two age groups over the years. There is an even bigger, and statistically significant, difference between the two age cohorts on Hillary Clinton‘s favorability: 57 percent among older Millennials, 47 percent among younger Millennials. In addition, there is probably a similar difference among likelihood of voting in 2014. The Harvard IOP people don’t provide the data here, but they do report that stated likelihood of voting is greater among Republicans, conservatives and whites than among Democrats, liberals and blacks and Hispanics.