Chapter 6 Indexes, Scales, And Typologies

Chapter Outline Indexes versus Scales Index Construction Scale Construction

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.

Index and Scale: Scoring Differences Index: accumulate scores assigned to individual attributes. Scale: assign scores to patterns of responses.

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

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

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.

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.

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.

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.

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.

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).

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.