Sources and methodology

How a number gets from an official page onto this site, and what happens when it changes.

What counts as a source

A source is a published page from the body that actually runs the scheme: GOV.UK, a government department, a local authority, an energy supplier, a regulator, or the charity or trust that administers a grant.

Another website's summary is not a source, no matter how well written. If we cannot find the rule published by the body that applies it, we do not publish a figure.

How we record it

When we take a figure from a source we store four things: the value, the page it came from, the date the value takes effect, and the date we checked it. We also keep a copy of the source page as it looked at the time, so a later rewrite cannot erase the evidence for what we published.

Every figure also records which part of the UK it applies to. Rules often differ between England, Scotland, Wales and Northern Ireland, and treating a England-only rule as UK-wide would send people to the wrong scheme. Our pages say which country they apply to.

How we notice changes

We re-read the sources we depend on automatically, on a schedule that depends on how often each one tends to change. When a page we rely on changes, the change is scored: a corrected typo is ignored, a changed amount or eligibility rule is flagged for a person to review.

We identify ourselves honestly when we do this and we respect the rules each site publishes for automated visitors. There is more detail on our crawler page.

When sources disagree

Sometimes two official pages give different figures — usually because one has not been updated yet. We do not average them and we do not silently pick one. The conflict is recorded and a person decides, using the date each figure takes effect and which body has authority over the scheme.

Calculators

Our calculators use the same stored figures as our pages. Each tool lists the rates it used and when they were last checked, so you can trace any result back to its source.

They produce estimates. They do not know your full circumstances, and they are not a decision about your entitlement.

Reading the dates

Last checked means the date a person or our monitoring confirmed the figure against its source. It does not mean the figure changed on that date. If a page carries no check date, we have not confirmed it and we say so on the page rather than showing a number.