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Index and Scales

Index and Scales. Review – What is a concept? What are indicators? Universe of meaning– possible meaning of concepts. Could have broad or narrow universe. Why use several indicators to capture the universe of a concept?. Particular element of meaning may be inadequate.

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Index and Scales

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  1. Index and Scales • Review – What is a concept? What are indicators? • Universe of meaning– possible meaning of concepts. Could have broad or narrow universe. • Why use several indicators to capture the universe of a concept?

  2. Particular element of meaning may be inadequate. • One indicator may not measure the aspect of the concept well. • Ideal for establishing reliability through use of parallel forms.

  3. Importance of composite measures • It is not easy to devise single questions to capture the complexities of certain concepts. • Indexes and scales reduce complex information to a single easy to understand score while maintaining the specific details of all individual indicators.

  4. Index • Summary measure of a complex concept obtained by adding up values of the indicators used to measure the concept’s universe of meaning. • Summated index – index made up of two indicators that have values: 1. Yes/agree and 0. No/disagree

  5. Do you favor mandatory coercive measures to correct community problems. • Mandatory employee drug testing • Drug testing for high school athletes • Mandatory seat belt use • Ban on new shopping center • Response: Favor=1 and Oppose=0.

  6. Complex Scales • · Scales are critical in showing intensity structures among the indicators. The items going into a composite measure may have different intensities in terms of the variable. Types of Scales Likert Scale

  7. Types of Scales Likert Scale • Consists of series of positive and negative opinion statements concerning a construct, each accompanied by a five- or seven point response scale

  8. Likert Scale measuring Self Esteem • Please check the single response option following each statement that most closely reflects your judgement. • I feel I have a 2. I feel I do not have • a number of good much to be proud of • qualities • ___ Almost always true __ Almost always true • ___ Often true __ Often true • ___ Sometimes true __ Sometimes true • ___ Seldom true __ Seldom true • ___ Almost never true ___ Almost never true

  9. Scoring – score almost always true 5 and reverse the scoring on the second question. Note that the first item is positively worded and the second item is negatively worded.

  10. Group Exercise • Try building a Likert Scale to test how serious college students are about their education.

  11. Semantic Differential Scale • Measure the multifaceted meaning of constructs. • Meaning of any concept can be represented as a point in semantic space formed by three dimensions: 1) Evaluation (E), represents a “good-bad” continuum of meaning 2) Potency (P) denoting “weak-strong” dimension 3) Activity (A), signifying an “active-passive” continuum of meaning.

  12. EXAMPLE. • When compared to female, male characters are: 1. Aggressive __:__:__:__:__:__:__ Submissive 2. Weak __:__:__:__:__:__:__ Strong 3. Logical __:__:__:__:__:__:__ Illogical 4. Withdrawn __:__:__:__:__:__:__ Outgoing 5. Sturdy __:__:__:__:__:__:__ Fragile 6. Insensitive__:__:__:__:__:__:__ Sensitive 7. Bold __:__:__:__:__:__:__ Timid 8. Dependent __:__:__:__:__:__:__ Self-reliant 9. Realistic __:__:__:__:__:__:__ Unrealistic

  13. Guttman Scale • Based on the fact that some items under consideration may prove to be more extreme indicators of the variable than others. • Anyone who gives a strong indicator of some variable will also give the weaker indicators.

  14. Suppose you are studying worker alienation in a factory and the indicators of alienation are: a)  Signing a recent petition against new work rules b)  Calling in sick a lot c)  Having filed a grievance against management in the past year.

  15. EXAMPLE. Table 1 below tests the assumptionthat those who have filed a grievance are likely to choose the first two. Sign petition Called sick Grievance No. + + + 20 Scale types + + - 12 + - - 8 - - - 2 Mixed Types - + - 2 + - + 2 - - + 1 - + + 1

  16. The Coefficient of reproducibility (CR) tests how closely any set of index data reproduces a perfect scale. • CR= 1 – (No. errors / No. of entries) • A coefficient of reproducibility of 0.90 or greater is accepted as a significant approximation of a perfect scale.

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