Audience affinity is a measure of the likelihood that people from a particular gender and age group and in a particular dimension are in the selected audience compared to the general population of Facebook (in the United States). This type of affinity can help you to isolate your ideal audience in terms of the gender/age grouping(s) you may want to target.
Dimension affinity is similar, but it measures the likelihood that people in a selected audience and from a particular gender and age group are in a particular dimension compared to the general population of Facebook (in the U.S.). This type of affinity helps you zero in more closely on your audience by identifying dimensions that you may want to target within a particular gender/age grouping.
Audience affinity gives results such as what you would see in an Audience Map. An affinity strength is rendered for each cell. This tends to reveal a pretty consistent pattern of strong affinity within a particular set of gender/age groupings. In the Audience Map below, that is women aged 25-54.
This is important to understand. But it’s even more impactful to know which dimensions within that group to target, something dimension affinity can tell you. The results of a dimension affinity analysis are presented in Targeting Ideas. The image below reveals the dimensions with the strongest dimension affinity for that audience of women aged 25-54.