A Defense of YouGov

I see lots of complaints about YouGov's downweighting of Yang voters. Really, this cycle just goes to show the limitations of online polling.

For a poll to have a valid sample of the population, you ought to have an equal chance of surveying any person in the population. But, with such a large population, this obviously can't happen. Exit polls kind of work, because your target population is "people who voted" and with enough interviewers you can get a good sample of that population, although there would be some clustering bias.

Landlines used to work well, because most of America had them, and would pick them up and respond to them. Moreover, few people had more than one land-line, so there was no chance of someone defrauding the system. However, with the advent of cell phones and scammers, fewer people have land-lines, and they are taking calls much much less. There's evidence that the type of person who does take calls is systematically biased. OP suggests that all polls should be done with the new technology. 96% of America owns a cell phone – but they are being picked up at an even smaller rate than landlines! So this type of technology also is biased. But, even though the pollsters have to make heavy assumptions about polling,

Now – to online polling. According to Pew Research, only 80% of Americans have a smartphone, and 74% have a computer. 14% of Americans access the internet once a week or less. These Americans are automatically excluded from any sampling framework. Moreover, most internet users have some number of email addresses they check regularly. I have 5 – work, alumni, spam, old personal, and new personal. So the equivalency between "mode of communication" and "person" or "household" has been broken. A company like YouGov gets a pool of internet users, who they hope roughly approximate the US population. Probably it isn't – it would exclude people who are disengaged from society – but they can hope.

The DNC sets polling requirements, and YouGov is included as a way for candidates to qualify. Knowing this, supporters of candidates (like the Yang Gang) sign up. Suspend disbelief for a second, and suppose YouGov did have a good representation of the US population before. Does the YouGov pool post-onslaught reflect the US population? Of course not! It would be systematically biased towards Yang (and any other candidate with an enthusiastic online following).

What are YouGov's options? They have no way to estimate the effect of the onslaught on biasing their polls. Some Yangsters have accused YouGov of simply downweighting Yang votes – and that would be a bad resopnse. But the response I understand from YouGov is that they're simply ignoring all recent sign-ups. Honestly, that's their best chance at a statistically valid sample here. But it is still is going to be biased – biased against people who were previously apathetic who Yang has activated. I'm really curious if Emerson polling sees a large split for Yang between land-lines and online polling – if so, and they don't correct for the Yang swarm, they may be biased in favor of Yang.