The rationale behind the "Half Flip" rating comes from a single statement Romney made on the issue.
PolitiFact (bold emphasis added):
But at a campaign event in Pittsburgh, Pa., a few months later, Romney offered a somewhat different perspective. His comments were videotaped and promoted by the liberal advocacy website Think Progress.PolitiFact detects a contrast between that statement and his other statements, as Romney typically acknowledges a role for humans in causing global warming while stating he doesn't think we know the degree to which humans contribute to the phenomenon.
A voter asked Romney, "What is your position on man-made global warming and would you reject legislation, such as cap and trade, which is based on the idea of man-made global warming?"
"My view is that we don’t know what’s causing climate change on this planet. And the idea of spending trillions and trillions of dollars to try to reduce CO2 emissions is not the right course for us. My view with regards to energy policy is pretty straightforward. I want us to become energy secure and independent of the oil cartels. And that means let’s aggressively develop our oil, our gas, our coal, our nuclear power."
In the summary paragraph, PolitiFact uses that difference to justify the "Half Flip" rating:
It’s unclear to us whether this was an inadvertent omission or a calculated attempt to say divergent things to different audiences. Because Romney, in our view, is savvy enough to know the difference between suggesting a human role in climate change and leaving it out, we think it’s reasonable to perceive Romney as taking two distinct stances in these two statements. We rate this a Half Flip.
It's fairly easy to illustrate this variation in precision using statements by PolitiFact editor Bill Adair regarding PolitiFact's process for choosing which statements to fact check.
Adair last year:
"We are a news organization and we choose which facts to check based on news judgment. We check claims that we believe readers are curious about, claims that would prompt them to wonder, 'Is that true?'"Adair this year:
"We try to check roughly the same number of claims by Democrats as we do for Republicans."In both cases Adair was addressing the issue of selection bias. Like Romney's statements on man-made climate change, Adair's descriptions differ from one another. PolitiFact would probably conclude that Adair is savvy enough about PolitiFact's operations to know that even back in 2011 that PolitiFact tries to check roughly ht same number of claims from either party.
But is that the correct conclusion?
It's more reasonable to take Adair as simply offering differing accounts of the same process. It's called "charitable interpretation," and PolitiFact struggles particularly in applying it to the claims of conservatives.
Regarding Romney, his statement was probably neither an inadvertent omission nor a calculated attempt to play to two different audiences. Romney simply used normal human language, complete with normal ambiguity, to communicate his position on climate change.
Heightening the aggravation of these types of PolitiFact findings, PolitiFact exempts itself from the "Burden of Proof" standard it applies to those it rates. A politician has the burden of proof for supporting his claims, PolitiFact says. But PolitiFact can claim a "Half Flip" just because it's supposedly "reasonable" to reach its conclusion.
It's hypocrisy lumped on top of a poor evaluation process.
And it's a "Full Flub" on the Flub-O-Meter.