Do pollsters miss any other large groups besides cell users?
Yes. They never, ever poll the 7 million Americans who live overseas (roughly the population of Virginia) even though all of them over 18 are eligible to vote in the state they previously lived in. These people are soldiers, teachers, missionaries, students, businessmen, and spouses of foreign nationals, to name just a few categories. Since they are such a heterogeneous group, they are hard to correct for.
