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Comparative ScalingComparative Scaling

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Some Key Concepts

Measurement Assigning numbers or other symbols to characteristics

of objects being measured, according to

predetermined rules.

Concept (or Construct)

A generalized idea about a class of objects, attributes,

occurrences, or processes.

Relatively concrete constructs Age, gender, number of children, education, income

Relatively abstract constructs

Brand loyalty, personality, channel power, satisfaction

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Scaling The generation of a continuum upon which measured

objects are located.

Scale A quantifying measure a combination of items that

is progressively arranged according to value or

magnitude.

Purpose is to quantitatively represent an items,persons, or events place in the scaling continuum.

Some Key Concepts

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Nominal

A scale in which the numbers or letters

assigned to objects serve as labels for

identification or classification.

Ordinal

A scale that arranges objects oralternatives according to their magnitude

in an ordered relationship.

Primary Scales of Measurement

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Interval

A scale that both arranges objects

according to their magnitudes and

Distinguishes the ordered arrangement in

units of equal intervals

I.e., indicate order and measure order (ordistance) in units of equal intervals

Primary Scales of Measurement

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Ratio

A scale that has absolute rather than

relative quantities and an absolutezero where a given attribute is absent.

Money & weight are good examples

of attributes that possess absolutezeros and interval properties.

Primary Scales of Measurement

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Scale

Nominal Numbers

Assigned 1 31 88

to Drivers/Cars

Ordinal Rank Order Third Second Firstof race finishers Place Place Place

Interval Championship

Points earned 170 175 185

Ratio Time to Finish,

behind winner 5.1 2.3 0.0

Primary Scales of Measurement

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Comparative Scales

Involve the direct comparison of

two or more objects Noncomparative Scales

Objects or stimuli are scaledindependently of each other.

Classifying Scaling Techniques

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Scaling

Techniques

Comparative

Scales

Paired

Comparison

Constant

Sum

Rank

Order

Noncomparative

Scales

ItemizedRating Scales

ContinuousRating Scales

Likert

Semantic

Differential

Stapel

Classifying Scaling Techniques

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Respondent is presented with two objects at atime

Then asked to select one object in the pair

according to some criterion Data obtained are ordinal in nature

Arranged or ranked in order of magnitude

Easy to do if only a few items are compared. If number of comparisons is too large,

respondents may become fatigued and no longer

carefully discriminate among them.

Paired Comparison Scaling

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Paired Comparison Scaling: Example

Cunningham Day Parker Thomas

Cunningham 0 0 0

Day 1 1 0

Parker 1 0 0

Thomas 1 1 1 0

# of times

preferred

3 1 2 0

For each pair of professors, please indicate the professor from whom

you prefer to take classes with a 1.

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Respondents are presented with severalobjects simultaneously

Then asked to order or rank themaccording to some criterion.

Data obtained are ordinal in nature

Arranged or ranked in order of magnitude

Commonly used to measure preferences

among brands and brand attributes

Rank Order Scaling

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Rank Order Scaling

Instructor Ranking

Cunningham 1

Day 3

Parker 2

Thomas 4

Please rank the instructors listed below in order of preference. For the

instructor you prefer the most, assign a 1, assign a 2 to the instructoryou prefer the 2nd most, assign a 3 to the instructor that you prefer 3rd

most, and assign a 4 to the instructor that you prefer the least.

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Respondents are asked to allocate a constantsum of units among a set of stimulus objects

with respect to some criterion

Units allocated represent the importanceattached to the objects.

Data obtained are interval in nature

Allows for fine discrimination among

alternatives

Constant Sum Scaling

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Constant Sum Scaling

Instructor Availability Fairness Easy Tests

Cunningham 30 35 25

Day 30 25 25

Parker 25 25 25

Thomas 15 15 25

Sum Total 100 100 100

Listed below are 4 marketing professors, as well as 3 aspects that students

typically find important. For each aspect, please assign a number that reflects howwell you believe each instructor performs on the aspect. Higher numbers

represent higher scores. The total of all the instructors scores on an aspect should

equal 100.

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NonNon--Comparative ScalingComparative Scaling

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NoncomparativeRating Scales

Continuous

Rating ScalesItemized

Rating Scales

Semantic

DifferentialStapel Likert

Classifying Noncomparative Scaling Techniques

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Continuous Rating Scale

Example

Very

Poor

Very

Good

0 10 20 30 40 50 60 70 80 90 100

X

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Method of Summated Ratings:

The Likert Scale

Extremely popular means for measuring

attitudes.

Respondents indicate their own attitudes bychecking how strongly they agree/disagree

with statements.

Response alternatives: strongly agree, agree, uncertain,

disagree, and strongly disagree.

Generally use either a 5- or 7-point scale

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Semantic Differential Scales for

Measuring Attitudes Toward Tennis

Exciting ___ : ___ : ___ : ___ : ___ : ___ : ___ : Calm

Interesting ___ : ___ : ___ : ___ : ___ : ___ : ___ : Dull

Simple___ : ___ : ___ : ___ : ___ : ___ : ___ Complex

Passive ___ : ___ : ___ : ___ : ___ : ___ : ___ Active

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Stapel Scales

Modern versions of the Stapel scale place asingle adjective as a substitute for the

semantic differential when it is difficult to

create pairs of bipolar adjectives. The advantage and disadvantages of a Stapel

scale, as well as the results, are very similar

to those for a semantic differential. However, the Stapel scale tends to be easier

to conduct and administer.

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A Stapel Scale

for Measuring a Stores Image

Department

Store Name

+3

+2

+1

Wide Selection

-1

-2

-3

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Graphic Rating Scales

A graphic rating scale presents respondents

with a graphic continuum.

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Graphic Rating Scale Stressing

Pictorial Visual Communications

3 2 1Very Very

Good Poor

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Surfing the Internet is

____Extremely Good

____Very Good

____Good

____Bad

____Very Bad

____Extremely Bad

Surfing the Internet is

____Extremely Good

____Very Good

____Good

____Somewhat Good

____Bad

____Very Bad

Balanced Scale Unbalanced Scale

Balanced and Unbalanced Scales

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Summary of Itemized Rating Scale Decisions

1. Number of categories While there is no single, optimal number, traditional guidelines

suggest that there should be between five and nine categories.

2. Balanced vs. unbalanced In general, the scale should be balanced to obtain objective data.

3. Odd or even number of If a neutral or indifferent scale response is possible for

categories at least some of the respondents, an odd number of categories

should be used.

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Summary of Itemized Rating Scale Decisions (continued)

4. Forced versus nonforced In situations where the respondents are expected

to have no opinion, the accuracy of data may be

improved by a nonforced scale.

5. Verbal description An argument can be made for labeling all or many

scale categories. The category descriptions should

be located as close to the response categories as

possible.

6. Physical form A number of options should be tried and the best

one selected.

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Scale Evaluation

Scale

Evaluation

ReliabilityValidity

Test-RetestInternal

ConsistencyAlternative

FormsConstruct

Criterion

Content

Convergent

Validity

Discriminant

Validity Nomological

Validity

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Reliability

Extent to which a scale produces consistentresults

Test-retestReliability

Respondents are administered scales at 2 differenttimes under nearly equivalent conditions

Alternative-form Reliability

2 equivalent forms of a scale are constructed, then

tested with the same respondents at 2 different times

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Reliability

Internal Consistency Reliability The consistency with which each item represents the

construct of interest

Used to assess the reliability of a summated scale

Split-half Reliability

Items constituting the scale divided into 2 halves, and

resulting half scores are correlated

Coefficient alpha (most common test of reliability) Average of all possible split-half coefficients resulting

from different splittings of the scale items

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Validity

Extent to which true differences among the objects arereflected on the characteristic being measured

Content Validity

A.k.a., face validity

Subjective, but systematic evaluation of the representativeness

of the content of a scale for the measuring task at hand

Criterion Validity

Examines whether measurement scale performs as expected in

relation to other variables selected as meaningful criteria

I.e., predicted and actual behavior should be similar

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Construct Validity

Addresses the question of what construct orcharacteristic the scale is actually measuring

Convergent Validity

Extent to which scale correlates positively with other measures

of the same construct

Discriminant Validity

Extent to which a measure does not correlate with other

constructs from which it is supposed to differ

Nomological Validity

Extent to which scale correlates in theoretically predicted

ways with measures of different but related constructs

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Relationship Between Reliability and

Validity

A scale can be reliable, but not valid

In order for a scale to valid, it mustalso be reliable.

In other words,

Reliability is a necessary but

insufficient condition for Validity.

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Reliability and Validity on Target

Old Rifle New Rifle New Rifle Sunglare

Low Reliability High Reliability Reliable but Not

Valid

(Target A) (Target B) (Target C)