How did we decide whom to call, and where did we get their numbers? Our poll started with the voter file, a data set of nearly every registered voter in the country. We call voters off this list, which makes our poll a “registration-based sample.”
Not every pollster does this. Most national polls call telephone numbers at random, using a technique called random digit dialing.
In the abstract, there’s a fine debate to be had about which approach is superior. But we had no choice: It is hard or even impossible to conduct a poll of a congressional district with random digit dialing, since no lists exist of telephone numbers sorted by congressional district. CONT.
Nate Cohn, New York Times