‘Polling at’

After listening to Anthony Reuben’s talk at the Royal Statistical Society conference in Belfast, I thought much about “what we could do without”.

A oft-confusing phrase seen in articles and discussions of opinion polling is ‘polling at’. This article looks at problems with this phrase.

24

The author Owen Jones stated on Twitter:

Two numbers would haunt [a Tory] every single day: 24. That’s the percentage Labour was polling at the beginning of the 2017 general election campaign.

Aside from 24 being one number, 24% was Labour’s lowest Westminster vote intention estimate after the general election had been called. It was the estimated vote share from one YouGov poll conducted on 18–19th April.

Using all polling data from April 2019, polling averages and other means of estimation do not suggest Labour’s vote intention share was quite that low:

The increase in Labour support throughout the campaign was well-tracked. (Image: Polling Observatory)

House effects hunting

This is just one example of many on social media, but why can referring to a single point estimate of…