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[ Metric reference ]

Cohort Breakeven Birth Year

A birth-cohort marker for when learned convention overtakes direct object familiarity.

[ Code ]

CBB

[ Formula structure ]

The public formula describes structure.

  • CBB = min birth year where CLL_y >= DOF_y
  • Private calibration, weighting, and evidence ranking stay protected.

[ How to read it ]

The metric supports screening, not certification.

  • A later CBB suggests direct object familiarity persists for more cohorts.
  • An earlier CBB suggests the symbol depends on learned convention for many users.
  • Every reading depends on declared context and evidence quality.
  • Human validation remains first-order evidence.