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MEASUREMENT OF VARIABLES: OPERATIONAL DEFINITION AND SCALES

MEASUREMENT OF VARIABLES: OPERATIONAL DEFINITION AND SCALES. CHAPTER 8. HOW VARIABLES ARE MEASURED?. Two types of variables: Variable that lends itself to objective and precise measurement Variable that doesn’t lend itself to accurate measurement because of its subjective nature.

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MEASUREMENT OF VARIABLES: OPERATIONAL DEFINITION AND SCALES

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  1. MEASUREMENT OF VARIABLES: OPERATIONAL DEFINITION AND SCALES CHAPTER 8

  2. HOW VARIABLES ARE MEASURED? • Two types of variables: • Variable that lends itself to objective and precise measurement • Variable that doesn’t lend itself to accurate measurement because of its subjective nature. • Abstract notions  observable characteristic behavior  measurable in a tangible way  called operationalizing the concepts • Operational definition is a statement of the specific dimensions and elements through which a concept will become measurable

  3. OPERATIONAL DEFINITION: DIMENSIONS AND ELEMENTS

  4. OPERATIONAL DEFINITION: DIMENSIONS AND ELEMENTS

  5. SCALES • Nominal Scales: splits data into groups, e.g., men, women • Ordinal Scales: ranks data in some order, e.g., exercising for 20 minutes is good, for 30 minutes is better, for 40 minutes is best • Interval Scales: sets data on a continuum, e.g. 1 2 3 4 5 very low very high • Ratio Scales: starts with absolute zero and indicates proportion, e.g. 0 5 10 ten is twice as big as five

  6. MEASUREMENT: SCALING, RELIABILITY, VALIDITY CHAPTER 9

  7. Rating Scales Dichotomous Scales  yes or no answer Category Scales  uses multiple items to elicit a single response Likert Scales  to examine how strongly subjects agree or disagree with statement on a 5-point scale Semantic Differential Scales  several bipolar attributes are identified at the extremes of the scale Numerical Scales  similar with Semantic Differential Scales with number on 5 or 7 point scale are provided SCALING TECHNIQUES:1. Rating Scales

  8. SCALING TECHNIQUES:1. Rating Scales…con’t • Itemized Rating Scales  a 5 or 7 point scale with anchors is provided for each item and the respondent state the appropriate number on the side of each item • Fixed or Constant Sum Rating Scales  the respondents are asked to distribute a given number of points across various items, the sum is constant • Stapel Scales  measure both direction and intensity of the attitude toward the item under study • Graphic Rating Scales  placing a mark at the appropriate point on the line

  9. SCALING TECHNIQUES2. Ranking Scales • Ranking Scales • Paired Comparisons  used when, among small number of objects, respondents are asked to choose between two objects at a time. • Forced Choice  enables respondents to rank objects relative to one another, among alternatives provided. • Comparative Scales provides a benchmark or a point of reference to assess attitude toward the current object, event, or situation under study.

  10. GOODNESS OF MEASURES • Stability • Test-retest reliability • Parallel-form reliability • Internal Consistency • Split-half reliability • Interitem consistency reliability • Validity • Content Validity • Face validity • Criterion-Related Validity • Concurrent validity • Predictive validity • Construct Validity

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