Indexes, Scales, And Typologies

1
Chapter 6

• Indexes, Scales, And Typologies

2
Chapter Outline

• Indexes versus Scales
• Index Construction
• Scale Construction

3
Index and Scale

• Similarities
• Both are ordinal measures of variables.
• Both rank order units of analysis in terms of
  specific variables.
• Both are measurements based on more than one data
  item.

4
Index and Scale Scoring Differences

• Index accumulate scores assigned to individual
  attributes.
• Scale assign scores to patterns of responses.

5
Constructing an Index

• Select items for a composite index.
• Examine empirical relationships.
• Assign scores for responses.
• Handle missing data.
• Validate the index.

6
Selecting Items

• Criteria
• Face (logical) validity
• Unidimensionality
• General or specific
• Variance

7
Empirical Relationships

• Established when respondents answers to a
  question help predict how they will answer other
  questions.
• If two items are empirically related, we can
  argue that each reflects the same variable, and
  both can be included in the same index.
• Bivariate relationships - relationships between
  2 variables.
• Multivariate relationships - relationship
  between more than 2 variables.

8
Assign Scores for Responses

• Two basic decisions
• Decide the desirable range of the index scores.
• Decide whether to give each item in the index
  equal weight or different weights.

9
Ways to Handle Missing Data

• Exclude cases with missing data from the
  construction of the index and the analysis.
• Treat missing data as one of the available
  responses.
• Analyze missing data to interpret the meaning.

10
Validate the Index

• Item Analysis - internal validation.
• External validation - ranking of groups on the
  index should predict the ranking of groups in
  answering similar or related questions.

11
Techniques of Scale Construction

• Bogardus social distance scale - measures the
  willingness of people to participate in social
  relations.
• Thurstone scales - judges determine the intensity
  of different indicators.

12
Techniques of Scale Construction

• Likert scaling - uses standardized response
  categories.
• Semantic differential -asks respondents to rank
  answers between two extremes.
• Guttman scaling - uses an empirical intensity
  structure (most common).

13
Typologies

• Summarize the intersection of two or more
  variables to create a set of categories or types.
• Typologies are often created in an attempt to
  construct an index or scale the items you felt
  represented a single variable appear to represent
  two.
• It is extremely difficult, to analyze a typology
  as a dependent variable.