1. Indexes, Scales, and Typologies
Chapter 6
Indexes, Scales, and Typologies

2. Scaling and Index
Constructed by accumulating scores assigned to individual attributes.
Examples
Conservatism
Racism
Political Activity

3. FIGURE 6-1 Indexes versus Scales.
Both indexes and scales seek to measure variables such as political activism. Whereas indexes count the number of indicators of the variable, scales take account of the differing intensities of those indicators.

4. Scaling and Index You end up with a “score”.
It is an ordinal measures of variables.
It rank order units of analysis in terms of specific variables.
Its measurements are based on more than one data item.

5. Selecting Items Criteria Face (logical) validity Unidimensionality
General or specific
Variance

6. Empirical Relationships
Established when respondents’ answers to one 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.

7. 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.

8. 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.

9. Validate the Scale/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.

10. Techniques of Scale Construction
Likert scaling - uses standardized response categories.
Semantic differential -asks respondents to rank answers between two extremes.

11. FIGURE 6-5 Semantic Differential: Feelings about Musical Selections
The semantic differential asks respondents to describe something or someone in terms of opposing adjectives.

12. Typologies
The classification (typically nominal) of observations in terms of their attributes on two or more variables.
The classification of newspapers as liberal-urban, liberal-rural, conservative-urban, or conservative-rural would be an example.

13. Table 6-4 A Political Typology of Newspapers