Monday, April 21, 2014

PunditFact's PolitiMath

Here at PolitiFact Bias, we keep some tabs on what we call "PolitiMath"--the mathematical indicators that correspond (or not) to various positions on its "Truth-O-Meter" scale.

This week offers us another potentially informative case, as PunditFact looks at whether Michael Eric Dyson was accurate in claiming that Sunday morning political talk shows "usually" feature conservative white men.


In terms of math, this case is fairly simple.  PunditFact counted 25 percent of the Sunday show guests as conservative white males--a little short of a plurality.

PunditFact also shared parallel figures compiled by the left-wing Media Matters organization.  Media Matters put the figure for conservative white men at about 29 percent, which did count as a plurality.

"Usually" means more than half the time, so using PunditFact's count Dyson was off by 50 percent.  Using the Media Matters count, Dyson was off by about 42 percent.

PunditFact rated Dyson's claim "Mostly False":
Dyson described the Sunday shows as having been "given over" to conservative white males. While that phrase isn't exact, it does suggest a dominant presence. The numbers don’t back that up. Conservatives outman the liberals but by the time you drill down to white, male, conservatives, they lose much of the edge.

Dyson pushed too far on his adjectives. We rate the claim Mostly False.
We don't understand PunditFact focusing on "given over."  It is the extended phrase "mostly given over" that provides the basis for the fact check.  "Mostly" communicates a "given over" figure exceeding 50 percent.

Going by the "Principles of PolitiFact, PunditFact and the Truth-O-Meter," a "Mostly False" statement contains an element of truth.  We are unable to identify what PunditFact thinks is the element of truth in Dyson's statement.

This case featuring Dyson compares very naturally with PolitiFact Florida's rating of Sen. Marco Rubio's statement claiming Americans are mostly conservative.  PolitiFact Florida gave Rubio a "Half True" for that one, though only one of three polls had conservatives self-identifying in majority numbers.

We certainly think there's much to criticize in the way PolitiFact's fact checkers went about rating both of these claims, but in terms of PolitiMath we can set those concerns aside and simply look at how PunditFact's numbers correlated to the "Truth-O-Meter" rating.

By the two measurements PunditFact offered, Dyson was at least 42 percent in error.  That resulted in a "Mostly False" rating.  By three measurements, Rubio was correct on one and off by a maximum of 36 percent by the two polls that showed conservatives as the plurality.

It's easy to see how Rubio's statement could count as at least partly true.  One poll unambiguously supported him.  But Dyson?  Not so much.

That's how PolitiMath works, for what it's worth.


Edit 11/16/2014: Added Link to PunditFact article in 6th graph - Jeff

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