Comparative Scaling
Comparative scales involve the direct comparison of stimulus objects. The data must be interpreted in relative terms and have only ordinal or rank order properties.
It is also referred to as non-metric scaling since we’re comparing only two items due to the rank order.
Comparative scaling includes paired comparisons, rank order, constant sum scales, Q-sort and other procedures.
Paired Comparison
In this method, a respondent is presented with two objects and asked to select one according to some criterion. The data is ordinal in nature.
For example:
Do you like a blue pen or a black pen – based on weight or smoothness?
Which of the two brands of shoes do you prefer? Adidas or Nike?
Con: For larger number of objects, there are a large number of pairs. N*(n-1)/2
Rank order
In rank order scaling, respondents are presented with several objects simultaneously and asked to order or rank them according to some criterion. It is used to measure attributes of products and services, as well as preferences for brands.
For example:
Constant Sum Scaling
In this technique, respondents allocate a constant sum of unites, such as points or euros, among a set of stimulus objects with respect to some criterion.
For example: Respondents may be asked to allocate 100 points to attributes of running shoes in a way that reflects the importance they attach to each attribute.
Q- sort
Developed to discriminate among a relatively large number of objects quickly (rank large numbers of objects quickly).
This technique uses a rank order procedure in which objects are sorted into piles based on similarity with respect to some criterion.
For example: A respondent is given 100 cards about different things that we're asking them about. They are then asked to rank them by putting the cards in, say 11 piles. So they pick up a card and they see a brand name. If they don't like the brand name, they put it in a low pile. If they liked the taste of a product, they might put it in a high pile. Based on all these characteristics, the respondents put all the cards into the 11 piles. This way we have a rough sort of their relative importance.
It is also referred to as non-metric scaling since we’re comparing only two items due to the rank order.
Comparative scaling includes paired comparisons, rank order, constant sum scales, Q-sort and other procedures.
Paired Comparison
In this method, a respondent is presented with two objects and asked to select one according to some criterion. The data is ordinal in nature.
For example:
Do you like a blue pen or a black pen – based on weight or smoothness?
Which of the two brands of shoes do you prefer? Adidas or Nike?
Con: For larger number of objects, there are a large number of pairs. N*(n-1)/2
Rank order
In rank order scaling, respondents are presented with several objects simultaneously and asked to order or rank them according to some criterion. It is used to measure attributes of products and services, as well as preferences for brands.
For example:
- Rank 5 varieties of iced tea based on taste/labelling/brand name.
- Rank brands of watches based on design.
Constant Sum Scaling
In this technique, respondents allocate a constant sum of unites, such as points or euros, among a set of stimulus objects with respect to some criterion.
For example: Respondents may be asked to allocate 100 points to attributes of running shoes in a way that reflects the importance they attach to each attribute.
Q- sort
Developed to discriminate among a relatively large number of objects quickly (rank large numbers of objects quickly).
This technique uses a rank order procedure in which objects are sorted into piles based on similarity with respect to some criterion.
For example: A respondent is given 100 cards about different things that we're asking them about. They are then asked to rank them by putting the cards in, say 11 piles. So they pick up a card and they see a brand name. If they don't like the brand name, they put it in a low pile. If they liked the taste of a product, they might put it in a high pile. Based on all these characteristics, the respondents put all the cards into the 11 piles. This way we have a rough sort of their relative importance.
