If you don’t follow the immigration debate closely, you may be a bit confused. The left is increasingly angry with President Obama, calling him the “deporter-in-chief.” That’s because the total number of deportations during Obama’s tenure recently passed 2 million. As Dara Lind wrote last week at Vox, that pace puts him on track to “have deported more people by the end of 2014 than George W. Bush did in his entire eight years.” Immigration groups like America’s Voice and publications like Mother Jones have made the same point.

The right is mad at Obama, too—but for the opposite reason. They say he’s deporting far fewer people than Bush, and has failed to adequately enforce the country’s immigration laws. Responding to Lind’s piece, and more generally to the arguments of the left, Sean Davis of The Federalist accused her of “deport[ing] the truth on immigration stats,” protesting: “Obama is most definitely not the leading deporter of all time. In fact, total deportations in 2012 were the lowest they’d been since 1973.” You can hear similar arguments from right-leaning places like The National Review and think tank the Center for Immigration Studies.

How is it possible that the two sides could look at the same data and see such different things? The key is how you define the term “deport”—and what you think about a broad change in policy that started during the Bush administration and has continued under Obama.

Under Bush, the majority of immigrants that the U.S. sent home were simply “returned.” Nobody took their fingerprints or put a permanent mark on their immigration records. Instead, U.S. authorities put them on buses and sent them back across the border. Between 2001 and 2008, there were over 8.3 million of these informal “returns,” according to the Department of Homeland Security. There were, by contrast, just 2 million “removals.” Those are the more formal deportations—the ones that go through some form of individual review, with an officer if not a judge, and become part of deportees’ permanent records.

But in the second half of the Bush administration, DHS decided to up the number of “removals” and limit the number of “returns.” The government hoped to deter immigrants from sneaking back into the country by making it clear that the U.S. knew who they were—and could punish them more harshly if they showed up again. Under Obama, DHS has stuck with this policy. Between 2009 and 2012, the number of deportations and informal returns was roughly the same—about 1.6 million each. Add up all the relevant numbers, you’ll see removals are on track to end up higher under Obama than Bush (Lind’s point in Vox) but that removals plus returns will end up higher under Bush than Obama (Davis’ point in The Federalist).