Nate Silver, one of the nation's pre-eminent poll interpreters, voiced the exasperation of many when he tweeted: The. Polls. Have. Stopped. Making. Any. Sense." At this time of year, the difference between poll results can be explained by everything from who is being surveyed (are they "likely" voters or just "registered") to how many cell phone users (who are generally younger and from more diverse backgrounds) are contacted to how the questions are worded. And while top pollsters try to adhere to common standards and best practices, there is a lot of room for interpretation in the way each constructs their universe of respondents. Pollsters have realized that the days of interviewing voters purely via landline telephones are long gone. The future, like many industries, is heading online and onto mobile devices. For now, the most daunting question involves how to integrate cell phone users. At least 25 percent of Americans use only cell phones. But it is illegal to place robocalls to cell phones. So pollsters who conduct surveys using automated telephone dialing must use a human dialer to conduct live interviews with cell phone respondents. Why make such an effort? Because experts say cell phone users are not only demographically different from landline-only users, but they also tend to have different attitudes. And within another decade, a majority of the U.S. population could be using only cell phones.