What it is
A RIF is built from lists: the function, level, and location cut, and the selection criteria. Layoff selection audits look for the criteria in writing, the date the list was built, and the protected-class pattern. WARN and mini-WARN duties attach to the list size and the site.
What to do about it: Ask for the selection criteria in writing, and keep the notice date. Federal filing rules require a copy of the WARN notice on some claims, so the notice date sets your eligibility week.
Plain-language description of US practice, not legal, tax, or financial advice. The paired guide carries the citations, dates, and thresholds; the state pages carry the local windows.