The immediate problem is the rapid growth in the number of people who have only a mobile phone, and are thus excluded from surveys conducted by landline. About a quarter of Americans are now “cellphone-onlys” (CPOs) in the industry jargon, and this poses both practical and statistical difficulties. They are less likely to answer their phones, and less likely to participate in a survey when they do, says Frank Newport of Gallup, another polling firm. They often retain their telephone numbers, including the area code, when they move from state to state, so it is hard to know where they are. And it costs more to call a mobile phone in the first place.Pollsters try to get around some of these issues by weighting the responses to reflect the demographics of the population likely to vote. But that requires a lot of research, a bunch of assumptions, and unknown error built into the results.
But even if fears of a systematic bias prove unfounded, the fuss about CPOs points to a broader problem for pollsters: the ever-increasing difficulty of persuading Americans to take part in political polls. The proportion of those called who end up taking part in a survey has fallen steadily, from 35% or so in the 1990s to 15% or less now. Reaching young people is especially difficult. Only old ladies answer the phone, complains Bill McInturff of Public Opinion Strategies, a Republican polling firm.Another election issue is that because this was a census year, the state legislatures (or their designees) voted into office on Tuesday will be the ones redrawing congressional boundaries in each state in time for the next round of elections. Thus, the get-out-the-vote campaign is more important than usual in this midterm election because the political party that controls the legislature can control the redistricting, at least in most states. In California, Proposition 20 aims to have this done by a citizens' committee, not the legislature, so that will be another vote to keep track of on election night.
Finally, we can note that the candidates themselves are not a demographically random sample of the eligible-voter population. In particular, Jennifer Lawless and Richard Fox have updated their analysis of "potential candidates" for political office and conclude that:
women, even in the highest tiers of professional accomplishment, are substantially less likely than men to demonstrate ambition to seek elective office. Women are less likely than men to be recruited to run for office. They are less likely than men to think they are qualified to run for office. And they are less likely than men to express a willingness to run for office in the future. This gender gap in political ambition persists across generations and over time. Despite cultural evolution and society’s changing attitudes toward women in politics, running for public office remains a much less attractive and feasible endeavor for women than men.