2.Survey: Measurement and Scaling

2.3 Non-Comparative Scales

Classification of Scaling Techniques

 

Non-Comparative Scales: Continuous Rating Scale

Continuous Rating Scale – Respondents rate objects by placing a mark at the appropriate position on a line that runs from one extreme of the criterion variable to the other.

Continuous Rating Scale: Perception Analyzer

Itemized Rating Scales: Likert Scale

Likert Scale – Requires respondents to indicate a degree of agreement or disagreement with each of a series of statements about the stimulus object within typically five to seven response categories.

Listed below are different opinions about 7-Eleven. Please indicate how strongly you agree or disagree with each by using the following scale:

NOTICE the reversed scoring of items 2,4,5, and 6. Reverse the scale for these items prior analyzing to be consistent with the whole set of items, i.e. a higher score should denote a more favorable attitude.

 

Likert Scale: Examples

Some Commonly Used Scales in Marketing

Construct	Scale Descriptors
Attitude	Very bad	Bad	Neither Bad Nor Good	Good	Very Good
Importance	Not at All Important	Not Important	Neutral	Important	Very Important
Satisfaction	Very Dissatisfied	(Somewhat) Dissatisfied	Neither Dissatisfied Nor Satisfied / Neutral	(Somewhat) Satisfied	Very Satisfied
Purchase Intention	Definitely Will Not Buy	Probably will Not Buy	Might or Might Not Buy	Probably Will Buy	Definitely Will Buy
Purchase Frequency	Never	Rarely	Sometimes	Often	Very Often
Agreement	Strongly Disagree	Disagree	Neither Agree Nor Disagree	Agree	Strongly Agree

Itemized Rating Scales: Semantic Differential

Semantic Differential – A rating scale with end point associated with bipolar labels that have semantic meaning. Respondents are to indicate how accurately or inaccurately each term describes the object.

This part of the study measures what certain department stores mean to you by having you judge them on a series of descriptive scales bounded at each end by one of two bipolar adjectives. Please mark (X) the blank that best indicates how accurately one or the other adjective describes what the store means to you. Please be sure to mark every scale; do not omit any scale.

 

NOTE: The negative adjective sometimes appears at the left side of the scale and sometimes at the right. This controls the tendency of some respondents, particularly those with very positive
or very negative attitudes, to mark the right- or left-hand sides without reading the labels.

Semantic Differential Scale: Example

Measuring Self-Concepts, Person Concepts, and Product Concepts

 

orange – Each point corresponds to a mean or median of the respective scale.

Semantic profiles of shampoo brands “Herbal Magic” and “Elseve” in comparison with an ideal shampoo from consumers’ point of view

blue – Ideal shampoo

orange – Elseve

green – Herbal Magic

 

Itemized Rating Scales: Stapel Scale

Stapel Scale – An unipolar rating scale with 10 categories numbered from -5 to +5 without neutral point (zero).

Used as an alternative to semantic differential, especially when a meaningful pair of opposed adjectives is difficult to construct.

Please evaluate how accurately each word or phrase describes each of department stores. Select a plus number for phrases you think describe the store accurately. The more accurately you think the phrase describes the store, the larger the plus number you should choose. You should select a minus number for phrases you think do not describe it accurately. The less accurately you think the phrase describes the store, the larger the minus number you should choose. You can select any number, from +5 for phrases you think are very accurate, to -5 for phrases you think are very inaccurate.

 

Basic Non-Comparative Scales

Scale	Basic Characteristics	Examples	Advantages	Disadvantages
Continuous Rating Scale	Place a mark on a continuous line	Reaction to TV commercials	Easy to construct	Scoring can be cumbersome, unless computerized
Itemized Scales
Likert Scale	Degrees of agreements on a 1 (strongly disagree) to 5 (strongly agree) scale	Measurement of attitudes	Easy to construct, administer and understand	More time-consuming
Semantic Differential	Seven-point scale with bipolar labels	Brand, product, and company images	Versatile	Controversy as to whether the data are interval
Stapel Scale	Unipolar ten-point scale, -5 to +5, without a neutral point (zero)	Measurement of attitudes and images	Easy to construct, administer over telephone	Confusing an difficult to apply

 

Non-comparative Itemized Rating Scale Decisions

Number of categories

• Although there is no single, optimal number, traditional guidelines suggest that there should be between five and nine categories.

Balanced vs. unbalanced

• In general, the scale should be balanced to obtain objective data.

Odd/even no. of categories

• If a neutral or indifferent scale response is possible for at least some respondents, an odd number of categories should be used.

Forced vs. non-forced

• In situations where the respondents are expected to have no opinion, the accuracy of the data may be improved by a non-forced scale.

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.

 

Number of Scale Categories

Number of categories – Although there is no single, optimal number, traditional guidelines suggest that there should be between five and nine categories.

+ The greater the number of scale categories, the finer the discrimination among stimulus objects that is possible

– Most respondents cannot handle more than a few categories

Involvement and knowledge

• more categories when respondents are interested in the scaling task or are knowledgeable about the objects

Nature of the objects

• do objects lend themselves to fine discrimination?

Mode of data collection

• less categories in telephone interviews

Data analysis

• less categories for aggregation, broad generalizations or group comp.

more categories for sophisticated statistical analysis, esp. correlation based ones

 

Balanced vs. Unbalanced Scales

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

Balanced Scale:

Extremely good

Very good

Neither good nor bad

Very bad

Extremely bad

Unbalanced Scale:

Extremely good

Very good

Good

Somewhat good

Bad

Very bad

 

Odd or Even Number of Categories

Odd/even no. of categories – If a neutral or indifferent scale response is possible for at least some respondents, an odd number of categories should be used.

– The middle option of an attitudinal scale attracts a substantial # of respondents who might be unsure about their opinion or reluctant to disclose it

– This can distort measures of central tendency and variance

– Do we want/need “contrast” in controversial attitudes?

 

Forced vs. Non-Forced

Forced vs. non-forced – In situations where the respondents are expected to have no opinion, the accuracy of the data may be improved by a non-forced scale.

– Questions that exclude the “don’t know” option tend to produce a greater volume of accurate data

– Are respondents unwilling to answer vs. don’t have an opinion?

– Use “don’t know” or better “not applicable” option for factual questions, but not for attitude questions

– Use branching to ensue concept familiarity on the respondent’s side

 

Verbal Description

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.

– Providing a verbal description for each category may not improve the accuracy or reliability of the data vs. scale ambiguity

– Peaked vs. flat response distributions

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