Friday, September 1, 2017

PolitiFact disallows Trump's underlying point?

PolitiFact's defenders sometimes opine that PolitiFact always justifies its rulings.

We accept that PolitiFact typically includes words in its fact checks intended to justify its rulings. But we detect bias in PolitiFact's inconsistent application of principles when it tries to justify its ratings.

Our example this time comes from an Aug. 31, 2017 fact check of President Donald Trump's claim that illegal border crossings have slowed by 78 percent.

Zebra Fact Check on Aug. 30, 2017 published criticisms of the way PolitiFact and the Washington Post Fact Checker handled this claim. PolitiFact's latest version corrects none of the specified problems, including the failure to attempt a reasonable fact check of how much of a drop in illegal Southwest border crossings Trump can claim.

As with its earlier fact check, PolitiFact offers examples of various cherry-picked statistics, implicitly demonstrating that cherry-picking leads to a divergent set of outcomes:
Here’s how the number of apprehensions have changed:
• From July 2016 to July 2017, down 46 percent;
• From June 2017 to July 2017, up 13 percent;
• From November 2016 to July 2017, down 61 percent.
As I explained over at Zebra Fact Check, a serious attempt to measure a drop in border crossings explains the use of a proxy measure (border apprehensions) and then picks a representative baseline against which to measure the change.

Zebra Fact Check calculated a 56 percent change. calculated 58 percent.

PolitiFact has yet to make a reasonable attempt to establish a representative baseline. The best attempt in the cherry-picked set we quoted was the comparison of July 2016 to July 2017, showing a 46 percent change. That comparison suffers from offering a narrow picture, made up of individual months separated by a year in time. Also, 2016 was not a typical year for border apprehensions under the Obama administration. But at least it compared Trump to Obama in an apples-to-apples sense.

PolitiFact's 46 percent figure ends up in the ballpark with the 58 percent figure produced.

That's where the problem comes in.

Where is Trump's underlying point?

Back in 2008, PolitiFact Editor Bill Adair published an article trying to explain how PolitiFact treats numbers claims.
To assess the truth for a numbers claim, the biggest factor is the underlying message.
Adair used as one of his examples a claim by then-presidential candidate Barack Obama that his mixed-marriage birth was illegal in 12 states when he has born. PolitiFact found it was illegal in 22 states but rated the claim "Mostly True." That is the potential power of the underlying argument. If one makes Obama's claim into "My mixed marriage birth was illegal in many states when I was born" then it's essentially accurate, but you can drop Obama down to just "Mostly True" since he underestimated the number of states by 10.

Does Trump have an underlying point that illegal Southwest border crossings have decreased under his watch?

It appears that he does, and it appears that PolitiFact offers him no credit for it. PolitiFact's fact check shows no interest at all in Trump's underlying point.


Correction Sept. 1, 2017: Swapped out "Did" for "Does" in the third-to-last paragraph.

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