The panel talked about the difficulties of different polling methods. Franklin's Marquette poll uses random digit dialing, which means every working phone number — landline or cell phone — in Wisconsin has the same chance of being called. When people pick up, more than half tend to participate. But the desire to screen calls and avoid telemarketers has led to a pick-up rate of less than 10 percent.

For now, there's not a demonstrable partisan difference between those who do answer their phones and those who don't, so that low pick-up rate isn't necessarily a problem, Franklin said. But Maslin warned that pollsters are "on the brink" of that dynamic changing.

In polls conducted online, like YouGov, sample sizes are much larger than phone polls — but they're all voluntary participants, and data is generally collected over a longer period of time, Franklin said.

Those complications are one reason aggregation models like Jones' can provide a good measure, Wagner said — but if every poll is wrong, the aggregation results will be, too.

The panelists agreed that in the future, polling will likely be done with listed samples, thanks to help from "big data."