Paired Comparison Method of L.L. Thurstone, 1928

• Select a set of attitude statements toward an issue in question
• Each judge in a panel of 25 or more reads every possible pair of items
  • Each judge decides which item is more favorable to the issue
  • Obtain for each pair the proportion of times one item is more favorable to the issue
• Using these data and applying some mathematics, one computes precise scores for each item
• A precise but unwieldly method of attitude scaling:
  • One must assemble a panel of judges, who make many paired-comparisons:
  • For k items there are .5(k)(k-1) pairs--i.e., 300 paired judgments for 25 items.
  • Download a PowerPoint Lecture on Thurstone scaling from this site (and other forms of scaling)

Method of Summated Ratings of Rensis Likert, 1932

• Likert devised terms for five categories of attitude ratings:
  • Strongly approve, Approve, Undecided, Disapprove, Strongly Disapprove
  • Like Thurstone, Likert devised a statistical model to generate scores for these categories
  • He soon found that his complex scores correlated .99 with the assigned scores: 5-4-3-2-1.
• He typically added the scores on set of items, producing "The Method of Summated Ratings"
• For an application in politics, see British political attitudes

Scalogram Analysis of Louis Guttman, 1944

• Guttman assumed that some attitude items were more extreme than others
• Respondents who agree to the most extreme statement agree to the less extreme
• Scalogram analysis determines the consistency of the pattern of agreement: See Guttman scale analysis
• The coefficient of reproducibility assesses the consistency of the pattern
  • Reproducibility can be quite high still have many errors
  • Guttman scaling has become less popular in recent years

Semantic Differential of Charles Osgood, 1957

• Respondents are asked to choose between opposite sets of symbols when rating a concept.
• Example from a Eurobarometer survey of citizens' feelings toward "violence":
  • Respondents faced eight pairs of words relating to "violence--e.g.,
    • beautiful v. ugly
    • strong v. weak
  • Reponse patterns are analyzed in scoring.
  • See this site for semantic differential