Another way to do this is based on a paper by Fader &amp; Hardie [0] that uses a probabilistic model, instead of a regression-based one. It&#x27;s highly readable, and very intuitive. The technique workss particularly well when there&#x27;s only limited cohort data (e.g. early days of a startup) and you can&#x27;t just blend years of prior cohort data. A former colleague and I made a web-based implementation as a little weekend project if anyone wants to try it out: <a href="http:&#x2F;&#x2F;retentionizer.herokuapp.com" rel="nofollow">http:&#x2F;&#x2F;retentionizer.herokuapp.com</a><p>[0] <a href="https:&#x2F;&#x2F;marketing.wharton.upenn.edu&#x2F;files&#x2F;?whdmsaction=public:main.file&amp;fileID=341" rel="nofollow">https:&#x2F;&#x2F;marketing.wharton.upenn.edu&#x2F;files&#x2F;?whdmsaction=publi...</a>