(CNN) -- Poll of the week: A new Quinnipiac University poll finds that President Donald Trump's approval rating is 41%, with a disapproval rating of 54%. That's largely consistent with live-interview national polling taken the last few months.
When you break it down by race, Trump's approval rating is 9% among black voters. His disapproval rating is 85% among them.
What's the point: There is another poll out in which more than 30% of black voters supposedly approve of Trump's job performance. Trump's biggest fans have trumpeted this poll as a sign that he is breaking through with African-Americans. The problem is the poll is almost certainly incorrect.
Polls of higher quality such as Quinnipiac's -- probability-based polls that are transparent about their data -- have consistently found Trump's approval rating to be much lower. The President's approval rating in these polls completed since July has averaged 12% with African-Americans. His disapproval rating has averaged 84%.
Here's the thing though: It does actually seem that Trump has gained support among African-Americans since the 2016 election.
The network exit polls had Trump winning only 8% among black voters in 2016. Hillary Clinton took 89% of their vote. That is, Clinton won black voters by an 81-percentage-point margin.
Trump's average net approval rating (approval rating minus disapproval rating) with blacks right now is -72 points. In other words, he's shrunk his deficit by 9 points.
I would argue, though, that the President has made an even bigger improvement. To make an apples-to-apples comparison, we can look at a post-election Pew Research Center study with verified voters. Pew found that Clinton had an even larger margin 85-point margin with black voters, of 91% to 6%. If this study were correct, it would mean that Trump had doubled his black support since the election. (Note: Trump's approval rating with blacks in a Pew poll in June, not included in our average, was 14%. Again, this suggests he has gained since the election.)
Even with averaging, the African-American subsample in these polls is small enough that our current estimate of Trump's approval rating comes with a fairly wide margin of error. That's why I decided to look at the President's average approval rating since April in Gallup's tracking poll . Doing so gives us a total sample of about 2,500 black respondents, a fairly robust sample size.
In this Gallup data since April, Trump's approval rating has averaged 13%. His disapproval rating has averaged 84%. Both of which are slightly better for Trump than our average since July.
What's interesting is that when you compare Trump's approval rating in Gallup polling with the percentage of the vote he got against Clinton in every other ethnic or racial group, Trump is doing worse now than he did back in 2016.
Is it possible that these high-quality pollsters are simply missing black respondents who dislike Trump? Sure. That, though, is a theory without any evidence that I know of.
Could it be that some African-Americans are saying they approve of the President but they won't end up voting Republican in an election? Of course. Additionally, many black voters undecided on Trump may go with the Democrats in the end. That said, there doesn't seem to be any sign of that in polling from Marist College , Quinnipiac , Pew or The Washington Post . The Democratic margin on the generic congressional ballot with black voters isn't any greater in these polls than Trump's net approval rating among them would imply.
It just seems that for whatever reason the President has picked up a small, but statistically significant, amount of support among African-Americans. The fact that he has done so while losing support among all other racial groups makes it that much more impressive.
It's not clear that this shift in sentiment will make much of a difference in 2018. Democrats still hold a sizable lead on the generic congressional ballot. A lead large enough that they should win control of the House, if everything holds through November.
Still, the importance of even a slight shift in African-American voter sentiment shouldn't be underestimated. They make up greater than 10% of the US electorate, and more in key swing states like Florida, Michigan and Virginia.
If you were to apply the changes we see in Trump's approval rating among blacks compared with his vote share in 2016 and all other groups voted the same, it would mean a shift in the national margin of about 1 percentage point toward him. In these swing states mentioned, it could be even greater.
One point may not seem like a lot, but remember that's half of Clinton's national margin in 2016. George W. Bush was able to win 2004 in part because he made a small gain among black voters similar to that Trump seems to have made since his own election.
If Trump is able to hold on to his additional African-American support, it could aid him in 2020.
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