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Scaling Techniques in Social Research

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