Every figure on this site is a count of active licenses on a state register, deduplicated by licensee, refreshed nightly, and auditable back to its source.
A record counts when its register does not mark it dead (expired, revoked, inactive) — using the register's own status, and its expiry date where no status is published. Each licensee is counted once on a composite identity key, so a holder on multiple boards is never double-counted.
Thousands of raw state classifications normalize onto one ladder: apprentice, intermediate, journeyman, master, contractor, inspector. Apprentice licensing couples to registered programs in some states and not others, so pipeline ratios respect that per-state distinction.
Per-100k figures divide the licensed count by U.S. Census 2023 population estimates. They describe licensed supply relative to population, not employment.
Every state carries a documented note on what it licenses at state level. States whose registers we cannot yet read completely are omitted from published figures rather than shown low. National figures publish with per-state counts beside them.
As of 2026-08-09.