Overlap analysis provides a measure of the level of duplication within a group of products. The results of the analysis may be presented in Venn diagrams, such as the ones shown in Exhibits 7.14 and 7.15.
The analysis essentially creates a number of buyer groups, three in the case of the two brand analysis in Exhibit 7.14 — 'Only Coca-Cola', 'Coca-Cola and Pepsi' and 'Only Pepsi'. Drilling into these buyer groups helps marketers address related issues.
For instance, a brand manager might be interested in reducing the number of variants or pack sizes within the brand’s range. Besides reviewing other metrics, the brand manager should check whether there are brand buyers who exclusively buy (i.e. solus buyers) that variant. In the example in Exhibit 7.15, if variant blue is withdrawn from the market, the buyers that exclusively bought that variant (3.1% of the brand’s buyer) are the ones that the brand is most likely to lose.
To take an informed decision the brand manager might want to check what competitor brands fall within the repertoire of these buyers. She can do this by analysing these buyers’ basket of purchases.