Registered voters early. Likely voters later. Public polls serve their audience well by capturing the views of the electorate at an appropriate time and communicate precisely what group of voters they are including in their tabulations.
Early in a contest, before voters have focused on the candidates or the race, maybe even before they even know a seat is being contested later that fall, The Marist Poll, along with its NBC News partner offers a preliminary look at voters and candidates. This is when registered voters, the entire potential electorate, is measured. It is the only group of voters whose views can be legitimately assessed this early. CONT.
Lee Miringoff, Marist Institute for Public Opinion