eeMba ii rm unit-3.1 measurement & scaling a
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This document discusses various types of measurement scales used in business research including nominal, ordinal, interval, and ratio scales. It also describes commonly used scaling techniques such as rating scales, attitude scales, Thurstone scales, Likert scales, and semantic differential scales. The key aspects of valid and reliable measurement are highlighted, including selecting observable events, developing a mapping rule to assign numbers, and applying the rule consistently.
eeMba ii rm unit-3.1 measurement & scaling a
- 1. Course: MBA Subject: Research Methodology Unit-3.1 MEASUREMENT & SCALING
- 2. • Measurement and Scaling • Commonly used scales in business research • Reliability and Validity of scales.
- 3. Scales and Measurements • A scale is a technique to measure some thing. Scaling is used in ordering a series of items along sort of continuum. – they are methods of turning a series of qualitative facts into a quantitative series • Measurements are yardsticks – Measurement in research consists of assigning numbers to empirical events in compliance with a set of rules – • Hence, measurement is a three part process • (1) Selecting observable empirical events • (2) Developing a set of mapping rules i.e. a scheme for assigning numbers • (3) Applying mapping rule to each observation of that event. Example of studying people who attend a auto show
- 4. Different Scales • Nominal Scale • Ordinal Scale • Interval Scale • Ratio Scale
- 5. Nominal Scale • It is simply a system of assigning number symbols to events in order to label them. • example: assigning numbers to football players in order to identify them – just for convenience • no quantitative value • can not come out with a meaningful value • We use Mode as the measure of Central Tendency – e.g. classifying the residents of a city according to religious preferences.
- 6. Ordinal Scale • The lowest level of the ordered scale that is commonly used is the ordinal scale • This scale places events in order • E.g. Rank orders represent ordinal scales – a student’s rank in his graduation class involves the use of ordinal scale. • These scales have no absolute values – all that we can say is that one person is higher or lower in rank on the scale • E.g. Ram’s rank is 10 and Mohan’s is 40 – what do you conclude? • If a is greater than b and b is greater than c, then a is greater than c • just mentions greater than or less than , without stating how much greater or less • the appropriate method of central tendency is median
- 7. Interval Scale • It has the power of nominal and ordinal scale plus one additional strength • The concept of equality of intervals. • E.g. the interval between 1 and 2 equals the difference between 2 and 3. • In this case the intervals are adjusted in terms of some rule that has been established as a basis for making the units equal. • These scales can have an arbitrary zero – it lacks a true zero • The Fahrenheit scale is an example of an interval scale • Mean is the appropriate measure of central tendency
- 8. Ratio Scale • It incorporates all the powers of previous three Scales • They have an absolute or true zero of measurement • E.g. measurement of physical dimensions like height, weight, distance and area • Geometric mean or harmonic mean are the measures of central tendency
- 9. Sources of error in measurement • Respondent • Situation • Measurer – behavior, style and looks of investigator may encourage or discourage certain replies from the respondent • Instrument – e.g. use of complex words, ambiguous meaning etc.
- 10. Characteristics of Sound Measurement • Sound measurement must meet the following tests. • Validity • Reliability • Practicality
- 11. Test of Validity • It refers to the extent to which a test measures what we actually wish to measure. • It can also be thought of as Utility. • Validity is the extent to which differences found with a measuring instrument reflect true differences among those being tested.
- 12. Test of Reliability • A measuring instrument is reliable if it provides consistent results • E.g. if a scale is consistently overweighs objects by 5 kgs is a reliable scale but is not a valid scale • Reliability is concerned with estimates of degree to which measurement is free of random or unstable error.
- 13. Test of Practicality • This can be judged in terms of : • Economy • Convenience • Interpretability
- 14. Scaling • It is defined as ‘ the procedure for the assignment of numbers ( or symbols) to a property of objects in order to impart some of the characteristics of numbers to the properties in question’. • It describes the procedure of assigning numbers to various degrees of opinion, attitudes and other concepts – a scale is a continuum, consisting of the highest point and the lowest point
- 15. Important Scaling Techniques • Rating Scales: It involves qualitative description of a limited number of aspects of a thing or of traits of a person. • We judge properties of objects without reference to other similar objects. • These ratings are in the form of “like – dislike”, “excellent-good-average-below average-poor”. • In practice three to seven point scales are generally used
- 16. Rating Scale cont.. • There are two types of Rating scale- • (1) The Graphic Rating Scale : various points are usually put along the line to form a continuum and the rater indicates his rating. • E.g. How do you like the product?
- 17. Cont.. 2) The Itemized rating scale ( Numerical Scale) : • It presents a series of statements from which a respondent • Selects one as best reflecting his evaluation. • E.g. suppose we want to enquire as to how well does a worker get along with his fellow workers: a. He is almost always involved in some friction with fellow worker b. He is often at odds with one or more of his fellow workers c. He some times gets involved in friction d. He frequently becomes involved in friction with others e. He almost never gets involved in friction with fellow workers
- 18. Attitude Scale • Thurstone defined ‘Attitude’ as “the degree of positive or negative feeling associated with some psychological object like symbol, phrase, slogan, person, institution, ideal or ideas towards which people can differ in varying degrees.” • While measuring the attitudes of the people, we generally follow the technique of preparing the opinionnaire ( attitude scale) in such a way that the score of the individual responses assigns him a place on a scale. • People may conceal their attitudes and express socially acceptable opinions – They may not really know how they feel about a social issue – People may be unaware of their attitude about an abstract situation until confronted with real situation – even behavior itself is at times not a true indication of attitude. • E.g- Politicians kissing babies • Is this behavior a true expression of affection towards infants? No • Hence there is no sure method of measuring attitude.
- 19. Cont..• With all these limitations, several attitude scales were developed, they are : 1. Arbitrary scales: • Are developed on ad hoc basis and are designed largely on researcher’s own subjective selection of items – researcher himself first collects few statements or items which he believes are unambiguous and appropriate to a given topic – some of these instruments are selected for inclusion in the measuring instrument. • E.g. consider a company image study – • How do you regard company’s reputation : 1. As a place to work : Bad -- -- -- Good 2. As a institution of social responsibility : Bad -- -- -- Good • These scales are easy to develop and relatively less expensive • Demerits are – no objective evidence and we have to rely on researcher’s insight and competence
- 20. Thurstone Scale ( Differential scale ) • This has been developed using consensus scale approach – In this approach the selection of items is made by a panel of judges who evaluate the items in terms of whether they are relevant to the topic of area. • Detailed procedure : • 1) The researcher gather a large number of statements, usually 20 or more ; • 2) These statements are submitted to a panel of judges ( 50 to 300 judges ), requesting them to classify these statements into eleven groups. • Those statements which he/she considers most favorable to the object are put in the first group; those considered next most in the second group ……… those consider most unfavorable in the last group.
- 21. Cont.. • It may be noted here that only the neutral and the two extreme categories ( most favored and most unfavoured) on which the statements are to be judged are defined. The remaining eight are unlabelled to create the impression of equal appearing intervals between the three labels. • 3) The scale value of a statement is computed as the median position to which it is assigned by the group of judges. • 4) A final selection is made taking items or statements that are spread out evenly along the scale from one extreme position to the other and for which there are more judges’ agreement.
- 22. Cont.. • 3) Summated Scales ( Likert Scale ) • This scale consists of a set of items ( statements) to which the subject is asked to react. The respondents are asked to respond to each item in terms of several degrees of agreement or disagreement and the scores may be, for eg. strongly agree - 5 ; agree-4; undecided-3; disagree – 2; and strongly disagree – 1. Total score is obtained when all the weights are summated • 4)Semantic Differential (S D) Scale: • This is developed by Charles E.Osgood and others in 1957. The word Semantic means relating to meaning in language. SD scaling is an attempt to measure the psychological meanings of an object. This scaling technique is used rather easily in decisional survey research. Its main use has been in connection with comparison of brand and company images, determination of attitudinal characteristics of consumers and analysis of the effectiveness of promotional activities.
- 23. Cont.. • “The S D scale is a technique for psychological measuring of things, usually concepts or objects of people. It consists of a series or set of descriptive adjectives or phrases which are polar opposite”. They are generally classified into three categories • 1.Evaluative : Good – Bad ; Beautiful – Ugly; Clean – Dirty; • Fair-Unfair • 2.Potency : Large – Small; Strong – Weak; Thick – Thin; • Loud-Soft; Deep – Shallow. • 3.Activity : Fast – Slow; Active – Passive; Sharp-Dull. • The respondents are asked to describe the concept under investigation according to the set of scales using the method of rating. Thus, the technique enables an investigator to examine both the context and intensity of people’s attitudes.