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Measurement and Scaling


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Measurement and Scaling

  1. 1. Measurement & Scaling Deepika(01) Pratiksha(09) Pragati(13) Neha(15) Harsha(33) Naina(31) Yashraj(38)
  2. 2. •Agenda What is Measurement and Scaling? Types of Measurement Scales Criteria for Good Measurement 1 2 3 4 Scaling Techniques
  3. 3. Measurement • Researcher must follow rules. • Reasons for which numbers are usually assigned: • Permit statistical analysis for resulting data. • Measurement results What is Measurement and Scaling? •Introduction
  4. 4. Scaling • Eg: scale satisfaction level from 1 to 11 • Measurement is actual assignment of numbers • Scaling is process of placing the respondent on a continuum. What is Measurement and Scaling? •Introduction
  5. 5. Types of Measurement Scales Nominal Ratio Interval Ordinal
  6. 6. • Lowest level of measurement. • Numbers are assigned to the identification of an objects. • One-to-one correspondence between the number and objects. Nominal Scale
  7. 7. • Q. What is your religion? • 1.Hindusim • 2.Sikhism • 3.Christian • 4.Islam Number can not be added ,divided ,subtracted or multiplied. In Nominal Scale one can compute :-suare Frequency distribution, Mode, Chi-square test Example:
  8. 8. • Next higher level of measurement. • The Ordinal scale measurement tells whether an object has more or less characteristics than other but it can not tell how much more or less. • It includes quality ranking, ranking of the teams in tournament, socio-economic class etc. • One can compute: Median, percentile, quartiles of the distribution. •Ordinal Scale
  9. 9. • It takes care of the limitations of ordinal scale. • There is no absolute zero. • Difference in 2 adjacent value is constant. • Technically, numbers on an interval scale can be added and subtracted but not divided and multiplied. • All the techniques applicable to the previous scales is also applicable to interval scale. •Interval Scale
  10. 10. • This is the highest level of measurement takes care of all the limitations of all other scales. • Numbers on these scales have meaningful interpretation. • Ratio scale can be converted into other 3 scales but the vice- versa is not possible. • This is the only scale which has a Zero. •Ratio Scale 6’5” 5’4”5’3” 6’4” 5’11”5’10”
  11. 11. •Scaling Techniques Likert Semantic Differential Stapel Scaling Techniques Non-comparative Scales Comparative Scales Paired Comparison Rank Order Constant Sum Q- Sort Continuous Rating scale Itemized rating scale
  12. 12. • Direct stimulus of object • Relative in nature • Non-metric scaling •Comparative scaling technique
  13. 13. Eg: Preference for Toothpaste Brands Using Rank Order Scaling • Brand Rank Order • 1. Crest _________ • 2. Colgate _________ • 3. Close up _________ • 4. Pepsodent _________ • 5. Sensodyne _________ •Rank order comparison
  14. 14. Eg: Importance of Bathing Soap Attributes Using a Constant Sum Scaling Attribute Points • 1. Mildness 8 • 2. Lather 2 • 3. Shrinkage 3 • 4. Price 53 • 5. Fragrance 9 • 6. Packaging 7 • 7. Moisturizing 5 • 8. Cleaning Power 13 Sum 100 •Constant Sum Scaling
  15. 15. Eg: Obtaining Shampoo Preferences Using Paired Comparisons Recording form: Head & shoulder Clinic plus Dove Head & shoulder 0 1 Clinic plus 1 1 Dove 0 0 No. of times 1 0 2 preferred •Paired Comparison
  16. 16. • It discriminates among large number of objects • Ordinal in nature • Time consuming • Expensive •Q-sort Technique
  17. 17. •Non-Comparative Technique Continuous rating Itemised rating
  18. 18. •Continuous rating Allows the respondent to place a mark at any point among a line running between two extreme points Also called graphic rating scale. Has metric scaling It has interval or ratio scale Can be expressed using diagrams, smiley and scale
  19. 19. •Itemized Rating In this respondents are provided with a scale that has a number of brief descriptions associated with each response categories. Issues to be kept in mind : •No of catergories to be used •Odd or even categories •Balanced v/s unbalanced scales •Nature and degree of verbal description •Forced v/s non forced scales •Physical form It includes •Likert •Semantic diffrentiation •Stapel
  20. 20. •Likert scale Named after Mr. Rensis Likert Range of categories from strongly disagree to strongly agree Also called summated scale It takes longer to complete
  21. 21. •Semantic Differentiation Used to compare images of competing brands or services. Respondent is required to rate each attitude on a number of 5- 7 pt rating scale +ve and –ve descriptions can simetimes switch places - reduces tendency to just mark 1 side
  22. 22. •Stapel Scaling Ian stapel developed it Its presented vertically with an adjective in the middle and five data points abv and five data point below. No zero point is offered.
  23. 23. •Criteria for Good Measurement Validity Reliability Sensitivity
  24. 24. • It refers to the whether we are measuring what we want to. •Validity Content • Subjective Judgment for assessing the appropriateness of the construct. Concurrent • Measures the validity of new measuring techniques by correlating them to the established techniques. Predictive • The ability of one phenomenon at that point of time to measure another phenomenon at a future point of time.
  25. 25. •Reliability Its concerned with consistency, accuracy and predictability of the scale. It refers to the extent to which a measurement process is free from random errors. I. Test –retest II. Split-Half
  26. 26. •Sensitivity It refers to instrument’s ability to measure the variability in a concept. Sensitivity can be increased by adding questions or items to the scale. Instead of only Agree and Disagree we can add strongly agree and strongly disagree to the scale