Methodology
Seed data
The 51-state baseline comes from Leider, Colombo & Nerlino (2021), Education Policy Analysis Archives 29(100). The authors conducted a document analysis of every U.S. state education agency's (SEA) public credentialing documents between October and December 2019, plus each SEA's professional teaching standards. Read the paper (opens in a new tab) .
Use of AI in data collection and analysis
Beyond the 2019 baseline, the catalog has been re-verified, extended, and prepared for publication using an AI agent (Claude, Anthropic) under direct human supervision. The agent retrieved current SEA documents, extracted the relevant credentialing rules, drafted the per-state coding against the same coding scheme used for the 2019 baseline, traced pre-2019 statutory and case-law history, and produced the prose surfaces that wrap the underlying data. Every field continues to trace to a cited source URL with a retrieval date, and dated source snapshots are archived per state in the project repository for independent inspection. The 2019 baseline coding from Leider, Colombo & Nerlino (2021) was not generated by the agent; it is the authors' published document analysis, retained verbatim and used as the comparison point against which every subsequent re-verification is recorded.
AI-assisted extraction is fallible. The agent may misread an SEA regulation, conflate adjacent endorsements, miss a recent rule revision, or apply the wrong canonical category. Readers are asked to treat any field outside the original 2019 collection as provisional until cross-checked against the cited source URL, and to verify load-bearing claims directly with the SEA before relying on them. Corrections — including disagreements with the coding, missing history events, and broken or stale citations — are welcome via the form below.
Data captured
Each state record encodes, per the canonical taxonomy:
- The percentage of public-school students classified as ELs.
- Whether a bilingual education credential is offered, and (if so) whether it is available as a standalone certification, an add-on endorsement, or both.
- Whether an ELD credential is offered, and the same standalone/add-on breakdown.
- Requirements to earn each credential: completion of an approved program, coursework, practicum, content test, and (for bilingual) demonstrated proficiency in a non-English language.
- Whether SEI training is mandated for all teachers.
- Whether the SEA's professional teaching standards explicitly reference diverse / cultural / linguistic / EL students.
Provenance
Every fact-bearing field on every state record cites at least one source — each with a URL, a retrieval date, and an attribution to either the Leider et al. 2021 collection or the 2026 re-verification pass. A state record with no cited source cannot be published; the build refuses it.
Verification — current status
The 2019 baseline data is treated as a seed, not the published version. Before public launch, every state must be re-verified against the SEA's current public documents and move from its 2019 baseline coding to the 2026 verified coding. Track the per-state progress.
Reporting outdated or incorrect data
State credentialing requirements evolve regularly, and AI-assisted coding can introduce its own mistakes. Practitioners, SEA staff, and researchers who identify outdated, miscoded, or insufficiently cited entries are encouraged to flag them — field-level corrections from people who work with these credentials directly are preferred to reliance on the project's re-verification schedule alone.