How we use sources and data

Four different kinds of information

A source-backed statement identifies an outside publisher. A number you enter is your supplied scenario. A worked example uses explicit assumptions. A missing field stays unknown. These are kept separate so a plausible-looking total does not imply more evidence than we have.

Scope travels with the data

Source records include their scope, verification date and access method. A national price reference is not a local quote. Census identifiers identify geographic areas, not contractors or customers. A location label alone does not establish permit jurisdiction. Check the exact address and project with the responsible authority when requirements matter.

What we do not fill in

Unavailable local pricing, search demand, partner payments and profitability are not converted into zeros or estimated silently. Household counts and wage figures are not used as invented contractor-price multipliers. A published source may contain conflicting tables or be inaccessible to an automated check; those limitations belong in the source note and review.

Following a source

Look for supported claims and source links on each research page and the reference notes beside a calculator result. Check what the linked document actually covers before applying it to your own project or policy. Sources below are a starting catalog, not a claim that every source applies to every tool.

More help with this decision

• Compare contractor quotes: price, scope and missing work