People often reach issue positions by balancing several considerations. They may agree with a policy's goal but resist its cost, trust one level of government but not another, or apply different values in different domains. New facts and elite cues can therefore move a specific position without transforming a broader identity.

A defensible measure states the action and responsible institution, offers balanced alternatives, and keeps the underlying proposal constant across respondents. Separate questions are needed for direction, strength, importance, knowledge, and expected behavior.

Suppose a town is considering longer library hours financed by a small increase in property taxes. Asking whether residents support "stronger libraries" names an attractive purpose but hides the financing. Asking whether they support "another tax increase" names the cost but hides the service. A useful item describes both pieces. Even then, a yes response establishes support for that proposal; it does not prove that the resident understands the budget, considers the matter decisive, or favors every library program.

Video lesson: Public Opinion: Crash Course Government and Politics #33