Protocol, Annotated
The TLC trial operated under two dated protocols. Protocol v9 (dated August 23, 1994) was the pre-randomization version, in force during the entire August 1994 – January 1997 enrollment window. Protocol v10 (dated November 4, 1997) was written more than nine months after the last child was randomized and after all clinical treatment had concluded. Protocol v10 is the version NIEHS placed on its public website, and it is the version the scientific community has treated as authoritative.
This section reads the two protocols side by side, with scholarly commentary drawn from the published TLC literature, the NIEHS RFP Amendment, and the archived NIEHS TLC trial website. Each sub-page focuses on a single design element, presents verbatim text from every source that discusses it, and flags internal contradictions.
This is a scholarly-edition reading of the TLC protocol. It is meant to be read alongside the full scanned protocols, which are available in the reference library.
Blinding & Placebo Comparability
Nine sources. Five different blinding mechanisms. Three silences. The two protocol versions describe incompatible blinding methods in §4.6 and §9.1.1, and the scientific literature (2000, 2004) settled on a version that matches only one of four protocol-internal descriptions. The primary outcome paper (Rogan 2001 NEJM) omits the mechanism entirely.
Treatment Endpoint — in development
The 15 µg/dL stop rule, the pre-randomization evidence base, the non-linear dose-response, and the recoverable-IQ calculation.
Power Calculation — in development
The 3-IQ-point detectable difference assumption, its citation to Pocock 1994 (who actually said 1–2), the between-group separation that was never achieved, and the SEM ceiling.
Iron Status & Ferritin — in development
The protocol’s own endorsement of ferritin as the definitive marker of iron status, and its failure to operationalize that endorsement for randomized children.
Vitamin & Mineral Supplements — in development
The 1997 lead-contaminated supplement recall, the discontinuation of supplements during treatment, and the resulting window of uncorrected iron deficiency.
Protocol source documents: Protocol v9 scan (PDF) · Protocol v10 scan (PDF) · Protocol v10 archived NIEHS HTML · NIEHS RFP Amendment