Undocumented population ~22 million

A PLOS ONE study by MIT and Yale researchers uses administrative and operational inputs (visa‑overstay counts, border apprehension estimates, deportation flows and demographic outflows) in a population‑flow model and finds about 22.1 million undocumented immigrants in the U.S.; even conservative parameter choices give ~16.7 million. This is substantially higher than the commonly cited 11.3 million figure derived from household surveys. — If accurate, the upward revision rewrites the scale for immigration policy, budget planning, enforcement debates, and public perceptions about the size and composition of the undocumented population.