Measurement and Scaling
-
Upload
yashraj-tahilramani -
Category
Education
-
view
587 -
download
0
description
Transcript of Measurement and Scaling
Measurement & ScalingDeepika(01)Pratiksha(09)Pragati(13)Neha(15)Harsha(33)Naina(31)Yashraj(38)
•Agenda
What is Measurement and Scaling?
Types of Measurement Scales
Criteria for Good Measurement
1
2
3
4
Scaling Techniques
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
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
Types of Measurement
Scales
Nominal
Ratio
Interval
Ordinal
• Lowest level of measurement.
• Numbers are assigned to the identification of an objects.
• One-to-one correspondence between the number and objects.
Nominal Scale
• 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:
• 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
• 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
• 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”
•Scaling Techniques
Likert Semantic Differential
Stapel
Scaling Techniques
Non-comparativeScales
Comparative Scales
Paired Comparison
Rank Order
Constant Sum
Q- Sort Continuous Ratingscale
Itemized ratingscale
•Direct stimulus of object
•Relative in nature
•Non-metric scaling
•Comparative scaling technique
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
Eg: Importance of Bathing Soap AttributesUsing 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
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
• It discriminates among large number of objects
•Ordinal in nature
• Time consuming
• Expensive
•Q-sort Technique
•Non-Comparative Technique
Continuous rating
Itemised rating
•Continuous ratingAllows 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
•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
•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
•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
•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.
•Criteria for Good Measurement
Validity Reliability
Sensitivity
• 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.
Predictiv
e
•The ability of one phenomenon at that point of time to measure another phenomenon at a future point of time.
•ReliabilityIts 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
•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