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Index and Scales Review – What is a concept? What are indicators? Universe of meaning– possible meaning of concepts. Could have broad or narrow universe.

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Presentation on theme: "Index and Scales Review – What is a concept? What are indicators? Universe of meaning– possible meaning of concepts. Could have broad or narrow universe."— Presentation transcript:

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. a)Mandatory employee drug testing b)Drug testing for high school athletes c)Mandatory seat belt use d)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. 1.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

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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