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