I am trying to run some analytics based on direct mail campaigns. I'd like to see a cohort's total value of lifetime gifts when a first gift year was in X year. For example, if donors A, B and C all gave their first gift in 2015, I'd want to be able to see the value of all their gifts from 2015, 2016, 2017, 2018 and 2019. I'm trying to ultimately see the ROI of giving campaigns, but I want to look further than the first year the gift was given and see how that annual cohort preformed over the subsequent years. Any ideas on the best way to do this?
