Have Republicans changed views on evolution? Or have creationists changed party? Pew's (half-released) numbers don't add up ... - Cultural Cognition of Health

Okay. Something does not compute.

Last few days everybody is chortling about a shift in % of Republicans who say they don’t believe in evolution.

According to Pew Research Center, a higher percentage of Republicans agreed with the statement that “humans … have existed in their present form since the beginning of time”  in 2013 than in 2009.

One fairly annoying thing is that the information that Pew disclosed about the survey makes it impossible to determine what percentage of Democrats actually believe in “naturalistic” as opposed “theistic” evolution.

Pew’s survey item is bifurcated.  First, survey participants respond to the question, “Which comes closer to your view? Humans and other living things have [1a] evolved over time [OR] [1b] Humans and other living things have existed in their present form since the beginning of time?”  Those who select [1a], are then asked:

And do you think that [2a] Humans and other living things have evolved due to natural processes such as natural selection, or [2b] A supreme being guided the evolution of living things for the purpose of creating humans and other life in the form it exists today?

There are two obvious possibilities: [A] Republicans are “switching” from belief in evolution (naturalistic or theistic) to creationism; or [B] creationists are switching their party allegiances from Democrat or Independent to Republican &/or evolutionalists (theistic and naturalistic) are switching from Republican to Democrat or Indepedent.

Either [A] or [B] would be really interesting, but they would reflect very different processes.

Pew doesn’t tell us directly (why?! I don’t get the attitude of this Report; very un-Pewlike) but we should be able to deduce the answer from what they do report — the population %s and the partisan breakdowns on “creationism” in 2009 and 2013.

And in that case,the proportion of Ds & Is who are creationists would have to be correspondingly lower.

Alternatively, If the proportion of Rs who are creationists went up but the proportion of Ds & Is who are creationists stayed same, then [A]– Republicans are changing position — would be the right answer.

And logically, in that case, the % of the U.S. public overall who now say they are “creationists” would have had to have gone up .

Now that would be truly surprising — huge news — because the %s on creationism-vs-evolution haven’t changed for decades.

But not surprisingly, Pew reports that “the share of the general public that says that humans have evolved over time is about the same as it was in 2009, when Pew Research last asked the question.”:

The same fraction of the U.S. public — approximately 1/3 — believes in “naturalistic” evolution today as did then. The 33% who selected the “creationist” response to the bifurcated survey item in 2013 is statistically indistinguishable from the 31% who did in 2009.

So … if the population frequency of creationism didn’t increase, and the proportion of Republican’s who now identify as “creationists” did, either creationists are switching to the Republican party or “evolutionists” (theistic or naturalistic) must be switching to Democrat or Independent — option [B].

But, logically, then, the proportion of “evolutionsists” who are now identifying as either Democrat or as Independent must have risen by an amount corresponding to the increase in “creationists” now identifying as Republican, right?

Nope. Pew says that the division of “opinion among both Democrats and independents has remained about the same”:

So if the percentage of Democrats and Independents who identify as creationist has stayed constant, and the proportion of Republicans has increased, [A] –Republicans are “switching” their views on evolution– must be the answer!

But if the proportion of Republicans who are creationists has significantly increased while the division of “opinion among both Democrats and independents has remained about the same,” the total proportion of the population that embraces creationism must be significantly higher. . . . Except that Pew says “the share of the general public that says that humans have evolved over time is about the same as it was in 2009, when Pew Research last asked the question.”