Source hierarchy
- Government datasets and technical documentation.
- Current manufacturer manuals and official specifications.
- Derived calculations whose inputs and formulas are published.
- Secondary sources only when a primary source is unavailable.
Data publication rules
- Missing values remain missing; they are not converted to zero.
- State averages are labeled as state averages.
- Modeled values are labeled as estimates.
- Rankings exclude records that lack the required field.
- Material method changes receive a version number and changelog entry.
Corrections
Material errors are fixed in the dataset and documented with the date, affected field and nature of the change.
Commercial independence
No retailer payment, affiliate relationship, price or preference changes a climate score, cost index, research table or city rank. Commerce is disclosed and isolated on a dedicated page.
Safety boundary
Planning information is not electrical, engineering, medical, code or permitting advice.