Correspondence analysis (or brand mapping) is a technique which allows rows and columns of a data matrix, e.g. average satisfaction scores for several products, to be displayed as points in a two-dimensional space or map. It reduces a complicated set of data to a graphical display which is immediately and easily interpretable.

Brand maps are based on correspondence analysis.Brand mapping is often used in brand research by placing products and attributes together on a map. This allows close interpretation of company perceptions with a variety of product and service attributes simultaneously.Brands are most strongly associated with the attributes that are closest to them on the map. If products are placed close to each other on the brand map, it means they have a similar image or profile in the market.The relative association of brands with an attribute can be determined by drawing a perpendicular line from the attribute vector line (=line from the origin to the attribute point) to each of the brands.

The distance between the brand and the attribute is the distance between the attribute location and where the perpendicular line crosses the attribute vector line.The centre of the brand map (the cross on the map), represents the overall mean of each attribute, and is the centre around which the brands are dispersed. The more a brand tends to lie in a similar direction away from the centre as an attribute, the more a brand is associated with that attribute. This also means that brands and attributes near the centre of the maps are not differentiating. The length of an attribute vector represents the extent to which the brands differ on that attribute.Angles between the vectors represent correlations between attributes. The smaller the angles, the more correlated the attributes are.