“Pollster who got it right in 2016 says...”

How to spot a bad poll when the narrative says otherwise

A reader named Neil sent along the following article last yesterday and asked “what do you think of this analysis?”

Here’s the article: “Pollster Who Got It Right in 2016: Michigan a Dead Heat”

The article is referencing a recent poll from the pollster Robert Cahaly, who does work for the right-leaning firm Trafalgar Group. Their poll showed Biden with a one-point lead in Michigan. That is a notable departure from the generally very blue numbers we’ve seen from other pollsters such as EPIC-MRA and Fox News over the past few weeks.

The piece argues that since Cahaly’s polls were better than others in 2016 (that’s kind of true; he predicted that Trump would win in Pennsylvania) then he must have some secret sauce that is making his polls better than everyone else’s.

To be sure, the Trafalgar Group’s polls are statistically no better than a replacement-level pollster. According to FiveThirtyEight’s pollster ratings (the overall grades from which I disagree with, but which present some good …