Polling Winners and Losers in Indiana Primary

Donald Trump became the presumptive nominee of the Republican Party with his win in Indiana on Tuesday by a margin most polling firms missed. Here are the winners and losers.

Mr. Trump defeated his closest rival Texas Sen. Ted Cruz by a 16.6% margin, or 53.3% to 36.7%. He won nearly every county with the exception of five concentrated mainly in the Northeast; two of which, notably the more voter-rich Allen County, he barely won by a 0.8% margin.

Nevertheless, Indiana was the eighth consecutive state–and, ninth in the last ten to vote–where the polls underestimated Mr. Trump’s support, a trend we had been trying to highlight for readers. In addition to updating our pollster scorecard to reflect polling accuracy, we would again like to point out who did a good job and who missed the mark.

The top pollster in the Indiana Republican Primary was Gravis Marketing, a nonpartisan polling firm based out of the Sunshine State. A [content_tooltip id=”39612″ title=”Gravis Marketing”] conducted from April 28 to April 29 pegged Mr. Trump’s margin almost exactly–17%. While they underestimated the exact vote share for both Mr. Trump and Sen. Cruz, they nailed the percentage when you proportionately add undecided voters and adjust for the increase.

Well done Gravis Marketing! Worth noting, Gravis was also among the two top pollsters in the New York primary, as well. Following the Empire State, they also accurately polled the Northeastern five-state primary and, more interesting to our senior political analyst, identified a trend that hurt Sen. Cruz all the way across the country in Indiana.

“While we focus on the evangelical vote in a Republican Primary, we fail to underscore the growing importance of the Catholic vote,” said PPD’s senior political analyst Richard Baris. “Gravis Marketing was a canary in the mine regarding Sen. Cruz’s weakness among Catholics. While Mr. Trump carried evangelicals on Tuesday, he crushed him among Catholic voters.”

We also wanted to highlight and give credit to the [content_tooltip id=”39829″ title=”NBC/WSJ/Marist”], who performed rather poorly from Iowa to recent contests. They were penalized on the PPD Pollster Scorecard for consistently underestimated Mr. Trump’s support this cycle and overestimating Sen. Cruz. However, Marist clearly made much-need adjustments to their model.

In the Hoosier State, they missed the margin of victory by only 2 points, which will have a positive impact on their overall grade. Mr. Trump led by roughly 10 points on the PPD average of Indiana Republican Primary polls and it was only due to these two pollsters increasing the average.

Now, here comes the shaming.

The Mike Downs Center for Indiana Politics released what was clearly an outlier in this contest, but they did so at a time that makes us more than a little suspicious of them moving forward. The results were not weighed, the interviews began on April 13, yet the poll was released only a few days before the primary without explanation. For the record, a disclaimer at the bottom of the page and an appearance on Fox News the morning of the vote–only after days of allowing your flawed survey to be used as propaganda–is not particularly honest or ethical.

In future projections, ratings and contests, this survey will be significantly offset until it proves itself to be a reputable poll.