Good scale measurement

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Good scale measurement

  1. 1. CRITERIA FOR GOOD MEASUREMENT
  2. 2. Goodness of measurement • Make sure the accuracy of the instrument. For that: • Ensure not missing any dimension, element, and question. Nothing irrelevant. • Assess the “goodness” of measuring instrument. • Characteristics of a good measurement: Validity, Reliability, and Sensitivity – accuracy of the measuring instrument.
  3. 3. The Goal of Measurement: Validity and Reliability
  4. 4. Validity • The ability of an instrument to measure what is intended to be measured. • Validity of the indicator  Is it a true measure? Are we tapping the concept? • Abstract ideas (construct) but concrete observations. Degree of fit between a
  5. 5. Types of Validity • 1. Content validity • 2. Criterion-related validity • 3. Construct validity
  6. 6. RELIABILITY • The degree to which measures are free from random error and therefore yield consistent results • Stability and consistency with which the instrument measures the concept and helps to assess the goodness of a measure. • Maintains stability over time in the measurement of a concept. • Two important dimensions of reliability: (a) stability and (b) consistency
  7. 7. a. Stability of Measures • Ability of the measure to remain the same over time. • It attests to the “goodness” of measure because the measure of the concept is stable, no matter when it is applied.
  8. 8. Note • Reliability is necessary but not sufficient condition of to test of goodness of a measure. • A measure could be highly stable and consistent, but may not be valid. • Validity ensures the ability of the instrument to measure the intended concept.
  9. 9. Reliability and Validity on Target Old Rifle New Rifle New Rifle Sun glare Low Reliability High Reliability Reliable but Not Valid (Target A) (Target B) (Target C)
  10. 10. Sensitivity • Instrument’s ability to accurately measure variability in responses. • A dichotomous response category, such as “agree or disagree” does not allow the recording of subtle attitude changes. • A sensitive measure, with numerous items on the scale, may be needed. For example: • Increase items. Increase response categories. (Strongly agree, agree, neutral, disagree, strongly disagree). It will increases a scale’s sensitivity
  11. 11. Practicality • Validity, reliability, and sensitivity are the scientific requirements of a project. • Operational requirements call for it to be practical in terms of economy, convenience, and interpretability.
  12. 12. Conclusion: • It is important for marketers to measure attitude scales and marketers try to understand these scales and influence them to gain an advantage in the market.

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