Tuesday, 30 August 2011

Perceptual Mapping

Perceptual mapping has been used as a strategic management tool for about thirty

years. It offers a unique ability to communicate the complex relationships between

marketplace competitors and the criteria used by buyers in making purchase decisions

and recommendations. Its powerful graphic simplicity appeals to senior management

and can stimulate discussion and strategic thinking at all levels of all types of


Perceptual mapping can be used to plot the interrelationships of consumer products,

industrial goods, institutions, as well as populations. Virtually any subjects that can be

rated on a range of attributes can be mapped to show their relative positions in

relation both to other subjects as well as to the evaluative attributes.

Perceptual maps may be used for market segmentation, concept development and

evaluation, and tracking changes in marketplace perceptions among other uses.

Perceptual mapping involves two steps: (1) data collection and (2) data analysis and


Data Collection

Among the various mathematical and statistical methods used to produce perceptual

maps, POPULUS has found—and published research to this effect—that multiple

discriminant analysis provides the most reliable methodology. Among the reasons for

this are:

1. Discriminant analysis has a close linkage between product points and attribute


2. Discriminant analysis maps do not change if attributes are added that are linear

combinations of those already present in the perceptual space.

3. Discriminant analysis is alone in paying attention to “between product”

information, after scaling it so that “within product” differences are equal for each

dimension and uncorrelated. That means that DA uses a “yardstick” to give every

dimension common metric (in terms of equal unexplained variance).

4. Discriminant analysis is the most efficient method in terms of cramming into a

space of low dimensionality the most information about how products differ.

5. Unlike mapping based on distances or similarities, DA make use of attribute ratings,

which are easy and natural for respondents, and useful for their content even if

mapping is not done with them.

6. POPULUS research [Fiedler, 1996] has shown that DA was more successful that

Correspondence Analysis at reproducing a known map when the data were

distorted in various ways.

Employing this methodology, respondents are never asked about similarities among

products or subjects; they are asked to rate products on attributes, and similarities are

inferred from differences in respondents’ ratings.POPULUS - 2 - Perceptual Mapping

The data required for perceptual mapping thus comes from rating scales where the

subjects of the map, from products to populations, are described on the basis of

selected attributes. The validity of the map depends on both the overall set of

attributes and the subjects of the study as well as the subset of attributes and subjects

evaluated by each respondent.

Most studies suffer from too many attributes. Manufacturers and service providers see

hundreds of ways in which their products and services differ—or might differ—from

those of their competitors. Often the research analyst is unable to impose the

discipline necessary to develop a reasonably short list of attributes. In most studies, it

is usually desirable (or necessary) to select a subset of attributes for respondents to

rate. This can be accomplished by using one of two approaches:

1. Select a subset of most important attributes. Each respondent rates all attributes

on importance. The questionnaire is programmed to select a subset of the

important attributes for rating. This may assure more meaningful questionnaires for


2. Randomly select a subset of attributes. The questionnaire randomly selects a subset

of attributes for each respondent. This has the advantage that there will be roughly

equal sample sizes for each of the evaluative criteria. The obvious disadvantage is

that the respondent task may be less interesting.

Research by POPULUS has shown that the first alternative provides for a greater

correlation between discrimination and importance.

Data Analysis and Presentation

Multiple discriminant analysis uses the “F ratio” to determine attribute and product or

subject location in the perceptual space. The F ratio is a ratio of the variance between

ratings of different products/subjects to the variance of ratings within

products/subjects. In an attribute study, these variations among ratings are generally of

two types:

1. The differences between products/subjects, revealed in the difference between

average ratings for different products.

2. The differences within products, revealed in the differences among respondents’

ratings of the same product.

An attribute would have a higher F ratio either if its product averages were more

different from one another, or if there were more agreement among respondents

rating the same product.

Multiple discriminant analysis finds the optimal weighted combination of all the

attributes which would produce the highest F ratio of between-product to withinproduct variation. That weighted combination of attributes becomes the first

dimension of the perceptual map

Name : Varun Deshpande

Marketing Group 6

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