Comparative Scaling

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Comparative 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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Some Key Concepts

• 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.

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Figure 9.3 Primary Scales of Measurement
Primary Scales of Measurement
Primary Scales
Nominal Scale
Ratio Scale
Ordinal Scale
Interval Scale
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Primary Scales of Measurement

• 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 or alternatives
  according to their magnitude in an ordered
  relationship.

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Primary Scales of Measurement

• 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 (or
  distance) in units of equal intervals

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Primary Scales of Measurement

• Ratio
• A scale that has absolute rather than relative
  quantities and an absolute zero where a given
  attribute is absent.
• Money weight are good examples of attributes
  that possess absolute zeros and interval
  properties.

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Figure 9.4 Primary Scales of Measurement
Primary Scales of Measurement
Scale Nominal Numbers
Assigned 1
31 8
to Drivers/Cars
Ordinal Rank Order
Third Second First
of race finishers
Place Place Place

Interval Championship
Points earned
170 175 185
Ratio Time to Finish,
behind winner
5.1 2.3
0.0
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Classifying Scaling Techniques

• Comparative Scales
• Involve the direct comparison of two or more
  objects
• Noncomparative Scales
• Objects or stimuli are scaled independently of
  each other.

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Figure 9.5 A Classification of Scaling Techniques
Classifying Scaling Techniques
Scaling Techniques
Noncomparative Scales
Comparative Scales
Itemized Rating Scales
Continuous Rating Scales
Paired Comparison
Constant Sum
Rank Order
Likert
Stapel
Semantic Differential
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Paired Comparison Scaling

• Respondent is presented with two objects at a
  time
• 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.

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Paired Comparison Scaling Example
For each pair of professors, please indicate the
professor from whom you prefer to take classes
with a 1.
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
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Rank Order Scaling

• Respondents are presented with several objects
  simultaneously
• Then asked to order or rank them according 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

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Rank Order Scaling
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
instructor you 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.
Instructor Ranking
Cunningham 1
Day 3
Parker 2
Thomas 4
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Constant Sum Scaling

• Respondents are asked to allocate a constant sum
  of units among a set of stimulus objects with
  respect to some criterion
• Units allocated represent the importance attached
  to the objects.
• Data obtained are interval in nature
• Allows for fine discrimination among alternatives

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Constant Sum Scaling
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 how well 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.
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
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Non-Comparative Scaling
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Figure 10. 3 A Classification of Non Comparative
Rating Scales
Classifying Noncomparative Scaling Techniques
Noncomparative Rating Scales
Continuous Rating Scales
Itemized Rating Scales
Semantic Differential
Stapel
Likert
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Continuous Rating Scale Example
Very Poor
Very Good
X
0 10 20 30 40 50 60
70 80 90 100
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Method of Summated Ratings The Likert Scale

• Extremely popular means for measuring attitudes.
• Respondents indicate their own attitudes by
  checking 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

• A series of numbered (usually seven-point)
  bipolar rating scales.
• Bipolar adjectives (for example, good and
  bad), anchor both ends (or poles) of the scale.
• A weight is assigned to each position on the
  rating scale.
• Traditionally, scores are 7, 6, 5, 4, 3, 2, 1, or
  3, 2, 1, 0, -1, -2, -3.

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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 a
  single 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
1 Very
Very Good Poor
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Figure 10.4 Balanced and Unbalanced Scales
Balanced and Unbalanced Scales
Balanced Scale
Unbalanced Scale
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
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Basic Noncomparative Scales
Scale Basic Characteristics Examples Advantages Disadvantages
Continuous Rating Scale Place a mark on a continuous line Reaction to TV commercials Easy to construct Cumbersome scoring unless computerized
Itemized Rating Scales Itemized Rating Scales Itemized Rating Scales Itemized Rating Scales Itemized Rating Scales
Likert Scale Degree of agreement on a numbered scale Measurement of attitudes, perceptions Easy to construct, administer, understand More time consuming
Semantic Differential Numbered scale with bipolar labels Brand, product, company images Versatile Difficult to construct appropriate bipolar adjectives
Stapel Scale Unipolar numbered scale, no neutral point Measurement of attitudes images Easy to construct, can administer over telephone Confusing difficult to apply
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Table 10.2 Summary of Itemized Scale Decisions
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Table 10.2 Summary of Itemized Scale Decisions
(Cont.)
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Figure 10.6 Scale Evaluation
Scale Evaluation
Scale Evaluation
Validity
Reliability
Content
Test-Retest
Internal Consistency
Criterion
Alternative Forms
Construct
Convergent Validity
Discriminant Validity
Nomological Validity
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Reliability

• Extent to which a scale produces consistent
  results
• Test-retest Reliability
• Respondents are administered scales at 2
  different times 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 are reflected 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 or
  characteristic 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 must also 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)