Methodology: how we source and verify data

Source hierarchy

We prefer sources in this order and say which kind each value comes from:

1. Official text or notices of standards bodies and regulators (for example SAMR/SAC, MIIT, UL Standards & Engagement, IEC, UNECE, Standards Australia).
2. Manufacturer technical datasheets for named products.
3. Peer-reviewed papers, cited by DOI.
4. Accredited test laboratories and established trade press, used for dates and context only.

Verification status

Each value in the materials data has one of two labels:

• Verified The value was read directly in the cited document, and the document, page or table, test temperature and access date are recorded.
• Typical A typical range compiled from several manufacturer documents, not yet traced line by line. Do not use it for design.

The same labels appear in the JSON data, so software and AI assistants can tell them apart.

Preserving the evidence

For each cited document we record the access date, save a copy in the Internet Archive's Wayback Machine where the publisher allows it, and for PDF datasheets publish the SHA-256 checksum of the exact file we read. If a manufacturer later changes or removes a datasheet, readers can still see what the value was based on.

Test conditions matter

Thermal conductivity depends strongly on temperature and on the test method (guarded hot plate, heat-flow meter, hot-disk, laser flash). We always record the temperature and, where the datasheet states it, the method. Values measured under different conditions are not ranked against each other.

Conflicts and uncertainty

When sources disagree we show the range and the reason, for example two different publication dates reported for GB 38031-2025. We never resolve a conflict by guessing.

Use of software tools

We use search tools and AI assistants to find documents and draft text. They are never treated as a source. A value is only marked Verified after it has been checked against the cited document.

Review cycle

Standards pages are reviewed at least every three months and whenever a regulator publishes a change. Every change is recorded in the change log.