Your N Is Not Your N: What Population Genetics Knows About Your A/B Test

Population genetics has a threshold where fitness stops deciding outcomes: below 1/(2Ne), a real difference is inert and sampling decides. Wild Ne/N averages 0.10 to 0.11 across 192 estimates. Your A/B dashboard reports a census count, not an effective one, and the same arithmetic explains why rehiring restores headcount but not capability.