A type of scale (see “Scale, Measurement”) that includes a set of response choices to a closed-ended question (see “Question, Closed-Ended”) in a research study in which the first and last responses represent opposite ends of a spectrum (for example, “Completely appropriate” vs. “Totally inappropriate” or “Extremely difficult” vs. ” Extremely easy”) and the other response choices represent points between the two extremes. See also “Scale, Semantic Differential.”