Also called an Affinity Score or Fit Score, this is how similar a prospect is to other prospects who have previously shown an affinity for a nonprofit, campaign, cause, company, or product/service. This part’s important: this isn’t a likelihood or probability. You’re not looking for high numbers, you’re looking for similarity among numbers. An affinity score of 38 is going to be super high-affinity if your previous prospects have an affinity score of 40. Again, we’re looking for closeness here — not rank.