Pedro Rojas holds a sign directing people to an insurance company where they can sign up for the Affordable Care Act, also known as Obamacare, before the February 15th deadline on Feb. 5, 2015 in Miami, Fla.

One of the Affordable Care Act’s most notable accomplishments is one of the reform law’s principal goals: lowering the nation’s uninsured rate. In the years since “Obamacare” was implemented, the percentage of Americans without health care coverage has fallen to the lowest levels on record.

In terms of the political implications of this success, however, there’s a broader question to consider: does the public know that the uninsured rate is the lowest it’s been in modern American history? As is too often the case, the answer depends on whom you ask.

The new Economist/YouGov poll, conducted last week, included several questions about Americans’ attitudes on the ACA, but the same survey also asked respondents a factual question about the health care system:

“Do you think that the proportion of persons without insurance has increased or decreased over the past five years?”

As a factual matter, we know with certainty that the answer is “decreased,” but overall, this detail is not widely known. The results found 37% of the public knows that the uninsured rate has gone down, while 31% believe it’s gone up, and 32% believe it’s stayed the same.

But look closer and predictable partisan divisions emerge: a plurality of Democrats believe, accurately, that more Americans have health insurance, while a plurality of Republicans believe the opposite. A clear majority (61%) of voters who backed Hillary Clinton answered the question correctly, while an even larger majority (74%) of voters who backed Donald Trump got it wrong.

The persistence of the “reality gap” continues to be a problem.

We talked a few weeks ago about a national Public Policy Polling survey that found Trump voters believing all sorts of wrong things, on issues ranging from unemployment (Trump voters believe it went up under Obama, which is the opposite of the truth), to the stock market (Trump voters believe it went down under Obama, which is the opposite of the truth), to the popular vote (Trump voters believe it went in the Republican’s favor, which is the opposite of the truth).

The partisan divisions over the efficacy of the Affordable Care Act are clearly part of the same phenomenon: Democrats and Republicans don’t just disagree about the direction of the country, they also seem to perceive reality in entirely different ways.

As we discussed earlier this month, some of these attitudes may be chalked up to tribal, reactionary instincts. Perhaps some Trump voters know, deep down, that the uninsured rate has improved dramatically once “Obamacare” was implemented, but they say the opposite solely because of their contempt for the president and one of his signature successes.

But I still think this explanation has limitations. It might explain some of the polling results, but not all. Indeed, as regular readers know, the “reality gap” isn’t altogether new: for years, many Republicans have told pollsters they believe border security has weakened under Obama (it’s actually strengthened), the deficit has gotten bigger (it’s actually shrunk by a huge margin), and the nation’s uninsured rate has gone up (it’s actually at an all-time low).

While the debate continues as to why the “reality gap” persists, the broader national conversation about these issues isn’t likely to be constructive until partisans have some shared reality upon which to build.