Criteria for a good scale


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Criteria for a good scale

  1. 1. Criteria for good Scaling
  2. 2. Meaning • Measurement – Assigning numbers or other symbols to characteristics of objects being measured, according to predetermined rules. • Concept (or Construct) – A generalized idea about a class of objects, attributes, occurrences, or processes. • Relatively concrete constructs – Age, gender, number of children, education, income • Relatively abstract constructs – Brand loyalty, personality, channel power, satisfaction
  3. 3. Meaning of scaling & scale • Scaling – The generation of a continuum upon which measured objects are located. • Scale – A quantifying measure – a combination of items that is progressively arranged according to value or magnitude. – Purpose is to quantitatively represent an item’s, person’s, or event’s place in the scaling continuum.
  4. 4. Primary Scales of Measurement Primary Scales Nominal Scale Ratio Scale Ordinal Scale Interval Scale
  5. 5. Primary Scales of Measurement • Nominal – A scale in which the numbers or letters assigned to objects serve as labels for identification or classification. • Ordinal – A scale that arranges objects or alternatives according to their magnitude in an ordered relationship.
  6. 6. Primary Scales of Measurement • Interval – A scale that both arranges objects according to their magnitudes and – Distinguishes the ordered arrangement in units of equal intervals – I.e., indicate order and measure order (or distance) in units of equal intervals
  7. 7. Primary Scales of Measurement • Ratio – A scale that has absolute rather than relative quantities and an absolute zero where a given attribute is absent. – Money & weight are good examples of attributes that possess absolute zeros and interval properties.
  8. 8. Primary Scales of Measurement Scale Nominal Numbers Assigned to Drivers/Cars 1 Ordinal Rank Order of race finishers Third Place Interval Championship Points earned 170 175 185 Time to Finish, behind winner 5.1 2.3 0.0 Ratio 31 Second Place 88 First Place
  9. 9. Criteria for good measurement: • Uni dimensional: considering single item at a time. • Validity: • Extent to which a scale produces consistent results (the effective ness) • Reliability: Getting the same result by repeating the measurement to over come the errors. Practicality: Measuring instrument can be judged in terms of economy(cost,time,resources etc).
  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. Relationship Between Reliability and Validity • A scale can be reliable, but not valid • In order for a scale to valid, it must also be reliable. • In other words, – Reliability is a necessary but insufficient condition for Validity.
  12. 12. Conclusion:
  13. 13. • Thanks a lot.