What is affinity analysis?

Affinity analysis is a type of data mining that gives similarity between samples (objects). This could be the similarity between the following:

• Users on a website, to provide varied services or targeted advertising
• Items to sell to those users, to provide recommended movies or products
• Human genes, to find people that share the same ancestors

We can measure affinity in several ways. For instance, we can record how frequently two products are purchased together. We can also record the accuracy of the statement when a person buys object 1 and when they buy object 2. Other ways to measure affinity include computing the similarity between samples, which we will cover in later chapters.