Robert J. Samuelson: Storm brewing over how opinion polls are taken

Less reassuring is telephone polling's steep and rising costs, which could cause cash-strapped media organizations to balk. Contacting cellphones is expensive, because numbers must be dialed by hand. By contrast, computers can automatically dial landline numbers, making it easier to reach live people. (Congress prohibited this for cellphones to protect people from paying for unsolicited incoming calls.) A typical survey costs Pew from $60,000 to $100,000, says Keeter. That would cover renting tens of thousands of landline and cellphone numbers to produce 1,500 interviews of about 20 minutes each.

The solution seems obvious: switch to the Internet. But technically, that's hard. Internet users may not be a representative sample of the U.S. population. Does the person behind that email live in the United States? Permanent panels of respondents may act differently from randomly contacted people. Experiments are under way. Meanwhile, pollsters are stretched between a past that's growing untenable and a future that doesn't yet exist.

Robert J. Samuelson is a Washington Post columnist.