Abstract: Methods for performing cohort decay analysis include operations of collecting, compiling, and organizing data about members of a group into member input data. The operations may also include determining activity periods for each of the members of the cohort and identifying unique data fields based on the data fields in the collected member input data. The operations may include performing synthetic cohort retention analysis and modeling on the unique data fields and determining at least one localized decay rate of the collected member input data for the unique data fields. The operations may include determining and modeling a decay rate for the collected member input data for the selected unique data field based on one or more localized decay rates. The operations may also include updating the localized decay rate, decay rate, and cohort retention model based on changes, additions, or deletions to the collected member input data.