Measurement of variable& scaling (2)

Measurement of Variables

How are variables measured?

• Office desk

• Demographic data

• Absenteeism (decision making when who is to be fired?)

• Blood pressure, height, weight.

• Perception, feelings and attitude (subjective)

Operational Definition or Operationalizing the Concept

Way of measuring abstract things to observable characteristics and behaviour.

Concept: Thirsty

Drink plenty of fluids

To determine the thirst levels of each individuals by measuring the quantity of fluid they consume to quench their thirst

Mc Cleland’s theory

• Need of Achievement

• Need of Power

• Need of Affiliation

Need of Achievement

Measure?

What behavioral dimension is observed within people driven by

high motivation?

1. Work round the clock or driven by work.

2. Unwillingness to relax

3. Work on their own

4. Challenging job but not too challenging where probability of success is low

5. Progress by getting feedback

Dimension 1: Work round the clock

• Working all the time( number of hours worker in a day)

• Persevere even in face of some setbacks

( nos. of setbacks experienced in task)

• Reluctance to take time off ( how frequently time off and for what reasons)

Dimension 2: Unwillingness to relax

• How often you think about work when you are away from workplace?

• What are your hobbies?

• How do you spend your time when you are away from the workplace?

Continuum of who relax very well to who relax very little

Dimension 3: Work on their own

No patience with ineffective people and are reluctant to work with others

Impatience with ineffectiveness

Dimension 4: Challenging job but not too challenging

Routine or stereotyped job description and other calling for gradations of challenge built into them

Those to opt for medium degree of challenge would have high achievement

orientation then lower or higher ones

Dimension 5: Progress by getting feedback

• Like feedback from superiors and even subordinates

• Appreciate both positive and negative

by keeping a track on how often individuals seek feedback from other during a certain period of time-say a month or more.

Continuum of extensive feedback to no feedback

1. To what extent you push yourself to get the work done?2. How difficult do you find it to continue in face of failures or discouraging

results?3. How often do you neglect personal matters because you are preoccupied

by your job?4. How frequently you think about ur job when away?5. To what extent you engage in hobbies?6. How disappointed you feel on not reaching goals you had set for yourself?7. How much do you concentrate on job?8. How annoyed you get when you make mistakes?9. To what extent u refer to work with a friendly but incompetent to one who’s

competent?10. To what extent u prefer to work yourself?11. To what extent you prefer a job that is difficult but challenging than easy to

routine?12. To what degree you prefer extremely difficult assignment to easy one?13. During 3 months, how often have you sought for feedback from superiors?14. During 3 months, how often have you sought for feedback from

coworkers?15. How often within 3 months you have checked with your subordinates that

what you are doing in not getting in their way of efficient performance/16. To what extent would it frustrate you if people did not give you feedback on

how you are progressing?

What is operational definition is not

• Not reasons, antecedents, consequences and correlates

• It describes observable characteristics

Exercise:

Operationalize concept of Learning and Stress

Scaling

• the process or result of

• observing an event or object

• in order to determine its extent or quantity

• by comparison with a known unit and

• then assigning numbers or any other symbols to characteristic or feature

• according to some prespecified formal rules.

There are four primary scales of measurement are

• Nominal (or categorical) scale

• Ordinal scale

• Interval scale

• Ratio scale

Nominal Scale

• does not express any values or relationships between variables

• the only mathematical or statistical operation that can be performed on nominal scales is a frequency run or count

• most of the demographic information collected is in the form of nominal scales

• categories are mutually exclusive and exhaustive

Example

• American• Australian• Chinese• German• IndianEvery respondent has to fit any one• Example 1 • Gender – male or female• Example 2 • Do you use Fair and Lovely soap?– yes or no• Example 3• Are you undergraduate, graduate or post graduate?

Exercise

• Suggest two variables that would be natural candidates for nominal scales and set up mutually exclusive or collectively exhaustive categories for each.

Ordinal Scale

categories have a logical or ordered relationship to each other (rank-orders the categories in a meaningful way)– permit the measurement of degrees of difference, but

not the specific amount of difference. – only possible to determine whether an object or

individual has more or less or equal amount of characteristic in comparison to any other – but NOT what amount of this characteristic

Example

• Example - Let there be 3 students A, B and C who respectively received 10, 12 and 20 marks in a test.

• The ranks would be – A – 1st B – 2nd C – 3rd

• • The quantitative (numerical) difference between

1 and 2 is the same as that between 2 and 3.• But the difference between the ranks, 1st and

2nd is NOT the same as that between 2nd and 3rd.

Exercise

Develop an ordinal scale for consumer preferences for different brands of beer

Interval Scale

• numbers are used to rate and assess objects so that numerically equal distances on the scale represent equal distances in the characteristic being measured

• distance between adjacent points on the scale is equal

• It helps to compute mean and standard deviation

• no true zero in this scale

Example

Let there be 4 students A, B, C and D who respectively received 4, 10, 16 and 20 marks in a test.

Is D doubly brilliant than B?Is A’s brilliance a quarter that of C’s?The quantitative (numerical) difference between A’s marks

and B’s is the same as that between B’s and C’sThe quantitative (numerical) difference between C’s marks

and D’s is thrice that between B’s and C’s.

Exercise

Develop Achievement motivation on the interval scale

Ratio Scale

• This scale consists not only of equidistant points but also has a meaningful zero point

• most sophisticated of scales, since it incorporates all the properties of nominal, ordinal and interval scales

Example

(1) Temperature measured in degrees Kelvin is a ratio scale. because absolute zero = meaningful zero point

0° K on the Kelvin scale = – 273.15 °C on the Celsius scale(2) If we ask 2 respondents their ages, difference between any two years would always be the

same‘zero’ would signify the absence of age or birth Hence, a 100-year old person is indeed twice as old as a

50-year old one. Sales figures, quantities purchased and market share are

all expressed on a ratio scale. (4) most commonly when respondents are asked for their

age, income, years of participation, etc.

Exercise

Mention one variable for each of the four scales in the context of a market survey and explain how or why it would fit into the scale.

Rating Scales

• Dichotomous scale

Elicits a Yes or No answer (nominal)

• Category scale

Multiple items to elicit a single response (nominal)

• Likert Scale Strong subjects on 5 pt scale

SD 1 D2 N3 A4 SA5

• Semantic DifferentialBipolar attributes identified at extremes of

the scale(interval)Responsive__ __ __ __ __ __ __Unresponsive

• Numerical 5pt or 7pt scaleExtremely pleased 7 6 5 4 3 2 1Extremly Displeased

• Itemized rating scale : 5 or 7 pt scale. Balanced scale with a neutral point

( unlikely & likely)

• Fixed or constant sum scaleChoosing the Toilet soap:1. Fragrance __2. Color __3. Shape __4. Size __5. Texture of Lather _______________________Total Points 100_____________________

• Stapel Scale: Simultaneously measures direction and intensity (interval)

Supervisor attributeThe picture of Sony TV is clear -5 -4 -3 -2 -1 clear +1 +2 +3 +4 +5

• Graphic Rating ScaleHow would you rate Sony TV on the following

scale?(ordinal)Type I: Extremely bad_________________________Excellent

• Consensus or Thurstone Equal Appearing Interval scale

• Multidimensional scaling- conjoint analysis

Ranking Scales

• Ordinal nature

• They do not give definitive clues

Paired comparison

the respondent is asked to select one of two items as the preferred or less preferred one according to some criteria.

Example – For each pair of TV indicate which one would you choose for your home viewing

Aiwa Akai LG Samsung

Sony

Aiwa ---

Akai ---

LG ---

Samsung

---

Sony ---

Forced Choice

• Example – Rank the following brands of TV as per your preference for home viewing (1 as the best and 5 as the worst).

• Aiwa _____

• Akai _____

• LG ____

• Samsung _____

• Sony ______

Comparative Scale

• deals with direct comparison of objects or individuals

• data collected is interpreted in relative terms

• data have only ordinal or ‘rank’ characteristics

• More Useful About same Less Useful

1 2 3 4 5

Many changes continue to occur in the healthcare industry. Because of increased competition for patients among providers and the need to determine

how providers can better serve their clientele, hospital administrators sometimes mail a quality satisfaction survey to their patients after patient is released. The following types of questions are sometimes asked on such a

survey. The questions will result in what level of data measurement?

1. How long ago you were released from the hospital?

2. Which type of unit were you in for most of your stay?

_Coronary Care

_Intensive Care

_Maternity Care

3. In choosing hospital, how important was the hospital’s location?

Very Important, somewhat important, not very Important, not at all important

4. How serious was your condition when you were first admitted to the hospital?

_critical _serious _Moderate _minor

5. Rate skill of the doctor:

_excellent _very good _good _fair _poor

6. Rate one to seven on nursing care

poor 1 2 3 4 5 6 7 excellent

Goodness of Measures

• Accurately measure

• Without redundancy

• Differentiate relevant and irrelevant things

1. Reliability

2. Validity

Reliability

Measures without bias, consistent across time and various items in instrument

• Test-retest reliability (across time)

• Parallel-reliability( changes in wordings and sequence)

• Interitem Consistency Reliability (Cronbach’s Coefficient)

• Split-half reliability

Validity

Authenticity of experimental design

Cause-effect relationships(internal)

Generalizability(external)

• Content Validity(face validity)

• Criterion related(Concurrent:difference is clear)

• Construct Validity(Convergent & Discriminant)

Any doubts?

Thank you