Kellstedt and Whitten, Chap. 5
Important concepts: validity and reliability.
Validity driven by two questions: face validity, which is essentially, "does this variable make sense?" and concept validity, which asks whether the variable measures what I think it measures.
Reliability based on coding. Can the same data, given to two coders with the same coding rules, get coded the same way? If yes, then reliable. If no, then not.
Wow, treating my methods class the way I treat other classes makes me sound kind of dumb. But it helps me learn the material, and no one's ever going to see these posts except me and hiring committees (who will understand, I hope).