What is Affinity Analysis?

Affinity analysis is the process of finding connections between dissimilar things based on a subject’s view of the items. One of the most basic examples of this is shampoo and conditioner. These two items are not directly related to one another, but purchasers often make connections between them since they are generally used at the same time. Affinity analysis is used in marketing and sociology fields as a way of understanding the motivations behind connected, but seemingly unrelated, events.

In order to use affinity analysis to find connections, a researcher must define a subject. While it is possible to perform a study on a single person, generally, the subject is a group of people that shares a number of important criteria. These criteria could be anything from shopping at a specific store, to falling within the same economic bracket, to living in the same town. In a more specific study, there may be dozens of criteria that each person in the group must have.

The next part of affinity analysis is observing and recording habits. After the group is established, the researcher can watch and record what the subjects do. After recording data, certain patterns will begin to emerge. In some cases, the patterns will be obvious, such as people who buy shampoo will often buy conditioner at the same time.

Occasionally, a pattern will form that seems to have no direct connection. For example, there is a direct correlation to the length of time a college student is in a stable relationship and his grades—the longer the relationship, the higher the grades. These two things seem to have no connection, but the data says otherwise.

These connections are the danger of affinity analysis. In the above example, there is actually no direct relationship. There is a third causal factor that is not being observed; the length of time the subject has been a student. The actual situation is much more direct. Older students, who have generally had more time to be in a long-term relationship, are more disciplined and likely to study and attend class.

Even with the difficulties in affinity analysis, it is a major marketing tool. By locating connections between products, even when the connection seems to make no sense, it’s possible to increase sales. These affinities are the cause behind a significant amount of product placement in major department stores. For example, in many stores, it is common to find a small end cap that contains condoms and sleep aids next to the sheets.