Inside the Meter

Guest column: Half-truths and the difficulty of fact-checking statistics

Editor's note: Jason Altimire is PolitiFact's Democratic guest columnist and a former member of the U.S. House of Representatives serving Pennsylvania’s 4th congressional district from 2007-13. Read more about the guest columnist position here.

In his first critique, Altmire is writing about a fact-check of a claim made by Rep. Markwayne Mullin, which you can read here. His post has been edited only for style and grammar.

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PolitiFact generously rates Congressman Mullin’s Facebook post "Half True." He got the numbers right, but failed to inform readers of the context. In evaluating claims involving the selective use of statistics, PolitiFact must consider whether the omission was accidental or meant to deceive. Mullin’s omission appears to have been purposeful, because he knows an evaluation of Obama’s entire economic record would present a completely different picture than the one the congressman was trying to paint. Is "Half True" an accurate rating in this case?

Merriam-Webster defines "half-truth" as "a statement that mingles truth and falsehood with deliberate intent to deceive." History’s master observer of political behavior, Niccolo Machiavelli, illustrated this point when he wrote that "occasionally words must serve to veil the facts." Two-and-a-half centuries later, Benjamin Franklin put it more bluntly: "Half the truth is often a great lie." (Yes, Franklin really did say that, as PolitiFact confirmed in 2013). By these measures, "Half True" is an accurate ruling.

Congressman Mullin is far from the first person to creatively use statistics to skew facts or obscure the truth. I would guess that every member of Congress has employed the same tactic at one time or another, and similar misuses of statistics are commonplace in every profession. Colgate famously saw its signature tagline banned when it was discovered that the "80% of dentists" surveyed who recommended the toothpaste had actually been recommending it as part of a group of competing toothpaste brands, not as a singular alternative to them. The claim wasn’t technically a lie, but it certainly didn’t convey the whole truth.

It is no wonder that the most widely read statistics book of all-time is Darrell Huff’s iconic How to Lie with Statistics, published in 1954. The book has been published in multiple languages and its message resonates with readers worldwide. In the book, Huff describes the various ways in which the misuse of statistics can be beneficial in making an argument when not all the facts are on one’s side. Huff goes to great lengths to evaluate the question at hand for PoltiFact: Is a person who is deliberately "lying with statistics" actually lying, or are they simply offering an incomplete version of the truth. (Spoiler: Huff comes to the same conclusion as Franklin and Machiavelli).

The irony of Congressman Mullin’s Facebook post is that he didn’t need to obscure the facts the make his point. If he had simply said it was a one year economic comparison between Trump and Obama, he would have been accurate. He would have fairly stated that Trump’s economic numbers were better in his first year in office than Obama’s were in his. Although critics would have justifiably mentioned the extraordinary circumstances of Obama’s first year economy, Mullin would have been correct. But scoring that point wasn’t enough. Mullin wanted to leave the impression that Trump’s record in office was better than Obama’s overall economic record. This is where the congressman ran into trouble.

PolitiFact gave the correct rating; Mullin’s post was indeed "Half True." But from now on, when readers consider a statement that has been rated "Half True" based upon the misuse of statistics, I hope they will remember the less-than-complimentary implication of that rating.