6.5 Measurement and Scaling Techniques

Measurement = the attributes' assignment of numbers (or symbols) by rules — the social world quantified. The measurement levels (the ladder to memorize): Nominal — the naming (the categories without order: the party's gender, the case's type); Ordinal — the ranking (the order without equal intervals: the satisfaction's "high/medium/ low"); Interval — the equal distances without a true zero (the attitude scores' conventions); Ratio — the equal distances with a true zero (the case's days, the docket's count). The rule: the level determines the mathematics (the nominal allows the mode, the ordinal the median, the interval-ratio the mean and the tests). The scaling techniques (the attitudes' measurement): The Likert scale — the agree-disagree ladder (the five-point summated ratings — the questionnaire's workhorse); The Thurstone scale — the equal-appearing intervals (the judges' pre-weighted statements — the classic, less used); The Guttman scale — the cumulative hierarchy (the items ordered so the agreement climbs); The semantic differential — the bipolar adjectives' rating (just-unjust, fast-slow — the court's image measured); The rating and ranking techniques — the direct assessments and the orderings. The measurement's quality tests: the reliability (the consistency — the same measure, the same result; the test-retest discipline) and the validity (the truth — the instrument measuring what it claims; the content validity — the items covering the concept; the construct…