I am calculating the differences between graduated betas v.s. discontinued betas for an academic paper.
When an unsuccessful beta is discontinued - e.g. Theoretical Physics - a note is placed "closed after 233 days in beta".
When a successful beta graduates, no note is placed - e.g. The Workplace - instead, there is a statement "This Stack Exchange site's beta was successful, so it launched 8 months ago" without exactly specifying how long the site was in beta.
How can I work out how long a successful beta was in beta phase for?