What’s inside

01

Branched cohort trees

Share one base table; each branch keeps an O(n) integer status vector, so branching never copies the underlying data values.

02

Exclusion provenance

cohort logs every exclusion with a human-readable reason and a serializable string predicate, ready to render as a CONSORT diagram.

03

Cached artifacts

Attach derived objects to any cohort and hand out mutation-safe copies to whatever consumes analytic data downstream.