Patrick Murray, Director of Monmouth University Polling Institute. | AP Photo/Mel Evans Poll conspiracy theorists target Monmouth's Patrick Murray

During the Republican presidential primary, frontrunner Donald Trump referred to Monmouth University pollster Patrick Murray as “highly respected.”

Trump’s supporters apparently now don’t feel the same way.


After weeks of Trump’s supporters promulgating conspiracy theories that pollsters have been rigging their results to boost Clinton, legions of Trump fans on Monday thought they saw proof of it in Murray’s methodology.

A Monmouth poll released that day showed Hillary Clinton with a narrow four-point lead over Trump in Ohio, a crucial swing state. Clinton’s lead was within the poll’s margin of error of plus or minus 4.9 points, so it wasn’t terrible news for Trump. And the poll showed Republican incumbent Sen. Rob Portman with an eight point lead over his Democratic challenger, former Gov. Ted Strickland.

But, pointing to methodology published by Murray, a Twitter user noticed that there were more self-identified Republicans than Democrats in the initial unweighted sample of respondents, but there were more self-identified Democrats than Republicans in the weighted sample used in the poll results.

Was Murray, whose poll has an A+ rating on FiveThirtyEight, risking his professional reputation in order to give Hillary Clinton a few points? Twitter exploded. Pro-Trump and conspiracy websites pounced.

“We demand investigation on this stupid guy,” a Twitter user wrote in one of the more family-friendly posts, “betcha he took money from crooked Hillary”.

Even a key Trump insider — Trump Organization attorney Michael Cohen, most famous for his recent “says who” exchange with a CNN reporter — tweeted an anti-Murray blog post.

Murray responded briefly on Twitter to the first user to accuse him of weighting the voter registration sample.

“We weighted by region age race gender and voter reg history,” he wrote. “But nice guess anyway.”

The user didn’t buy it, calling the explanation a “lie” and saying “the only weighting you changed was party ID.”

Pollsters routinely weight results to make up for groups over and under-representation in their initial samples. And Murray’s poll does show it was weighted for age. For instance, 176, or 44 percent, of the 402 respondents in the unweighted sample were under 50. In the weighted sample, they accounted for for 48 percent.

Not seen in the methodology Murray published, but shown in data Murray provided to POLITICO New Jersey, is that the most underrepresented age in the initial data was under 35 — the most Democratic-leaning age subgroup. Voters over 65 — those most likely to vote for Trump — were over-represented in the initial sample, accounting for 32 percent of respondents. In the weighted sample, they made up 24 percent.

“You’re not seeing we’re weighting the under 35s higher because we’re grouping them with the under 50s, who don’t get weighted as much. But it’s enough to move self-reported party IDs for Democrats a couple points,” Murray said.

Also weighted in Murray's poll, but not apparent in the published methodology, is voter race and regions of the state.

“In Ohio, we had a significant under-representation of voters from the northern part of the state by the lake,” Murray said. “We’re talking about Cleveland and Cuyahoga County, the biggest Democratic county in the state.”

Krista Jenkins, who runs Fairleigh Dickinson University’s PublicMind poll, said she saw nothing wrong with Murray’s methodology.

“If you draw a random sample, you’re going to end up with a fairly random snap-shot of the population, but inevitably some demographics will be overly represented. For instance, we know older people are easier to reach on the phone. You apply these statistical weights after you collect this data,” Jenkins said. “As long as the foundation of his polling methodology is sound, and it is, I see no reason to be critical of what he did.”

Murray, for his part, didn’t respond to the attacks in detail on Twitter. Instead, he retweeted several of the attacks aimed at him.

“It’s hard to explain on Twitter,” Murray said, “and quite frankly it would be wasting my breath.”