Jon Cohen of the Washington Post nails it:
bq. Only one of Monday’s five publicly released Massachusetts Senate polls asked prospective voters anything beyond their ballot preference, opinion of the candidates and a few demographics.
bq. …Good survey research clarifies, providing data about “why” prospective voters make choices, both in terms of whether they will vote and how they will cast their ballots. Producing a solitary horse-race number is essentially a publicity stunt. That number may end up hitting the mark, but without any explanatory information behind it, it’s of no value to understanding the election.