The Hill, today: Poll finds sharp swing in opposition to impeachment among independents
OMG, let’s find out about this “sharp swing.” It must be a doozy!
The latest national poll from Emerson College finds 45 percent oppose impeaching President Trump, against 43 percent who support it. That’s a 6-point swing in support from October, when 48 percent of voters supported impeachment and only 44 percent opposed.
… Except, hold on, no, that’s not a “six point swing” in opposition to impeachment. According to the just quoted numbers, opposition to impeachment rose by … one percentage point (44% to 45%). What apparently changed is support for impeachment, which changed from 48% in the first poll to 43% in the second (note that even this is not a six point change.)
No doubt that must mean that “Don’t know” or “No response” increased from 7% to 13% (but neither the Hill article nor the Emerson polling press release bothers to tell us what this third residual category is, exactly.)
What The Hill seems to be talking about to get a swing of six points is the difference between the “oppose” number and the “support” number.
If by chance you wanted to talk about the arithmetic difference in these situations, you should always use the word “net.” For example, “favorability” for a candidate is the straight percentage of people saying they view a candidate favorably. “Net favorability” is that value minus the percentage who view the candidate unfavorably. These are very different concepts, which is why they have different names! (E.g. national favorabilty for Trump is 42.3%. But Trump’s net favorability is -11.8%, vastly different.)
Does this poll show a major, dramatic shift in attitudes? No, not necessarily. The poll (and the poll before it, to which it is being compared) has a margin of error of 3%, meaning there’s a 95% chance the values measured by the poll are within 3 percentage points of their true value in the population.
Imagine this as a possibility: the true values for “support,” “oppose,” and “don’t know” are 45.5%, 44.5%, and 10% respectively, and that those values have not changed since October. That possibility is indeed within the margin of error for both polls.
But “New poll shows public opinion more uncertain about impeachment, or possibly unchanged” makes a crappy headline. And since The Hill skews towards Trump (they had conspiracy theorist John Solomon on their payroll as a legit reporter) they turn a change in “don’t know” to a major upswing in opposition to impeachment.
