Methodology and trust
Where the numbers come from, which ones are worked out rather than recorded, and what the data cannot tell you.
GovernedBy covers 1,173 ministers and 3,773 ministerial appointments since 1979. Every headline number is computed from the data and checked before it is published. We never name a cause we cannot show.
1. What is recorded
These come straight from public records. Who held which post, and when, comes from the Institute for Government Ministers Database (CC-BY-4.0). Everything else is attached to it.
| What | Source | Limits |
|---|---|---|
| Posts, departments, ranks, dates | Institute for Government Ministers Database | Complete and curated. |
| Seats, party, Commons and Lords service | UK Parliament Members API | Boundaries change, so a seat name does not always mean the same area. |
| Votes | Commons and Lords Votes APIs | 2016 onwards only. |
| Election results | Parliament Members API and the House of Commons Library | 2010 onwards only. |
| Jobs after office | Advisory Committee on Business Appointments (ACOBA) advice letters | Only jobs someone asked about. |
| Outside earnings, visits, gifts | Register of Members' Financial Interests | Current register, sitting MPs only. |
| Overseas ministerial travel | Departmental transparency releases on GOV.UK | Formats vary, so a few trips may be unmatched. |
| Birth, birthplace, education | Wikidata, then Wikipedia where Wikidata is silent | Thinner for older and less prominent ministers. |
| Careers before Parliament | Wikipedia career sections, read by AI assistants | A reading of prose, not a record. Each entry keeps its source sentence and a confidence score. |
2. What is worked out
These rest on our own rules. Each article repeats the caveat that matters for it.
| Finding | How | Read it as |
|---|---|---|
| Why a post ended | The first rule that fits, in order: another post within three days; death; lost their seat; the governing party changed; a new prime minister, or eight or more ministers leaving in a day; a resignation stated in their Wikipedia article. Outgoing ministers conventionally "resign" when a new prime minister arrives, so those count as dropped. | An estimate. Resignations are a floor. "Not recorded" hides sackings and resignations the biographies omit. |
| Instant peers | Never sat in the Commons, and a peerage began within 120 days of first appointment. | A definition. The window is our choice. |
| Political families | Wikidata lists a parent who sat in Parliament or the Lords. | A floor. Wikidata is better for some families than others. |
| Student-society presidents | The Wikipedia article carries a category such as "Presidents of the Oxford Union". | A floor. Articles without the category are missed. |
| Seat safety and seats lost | Previous-election majorities and candidate results. | Reliable from 2010. For 2024, old-boundary majorities are compared with new-boundary results, so approximate. Earlier losses are undercounted. |
| Rebellions | A vote against the majority of the minister's own party, outside free votes. A vote is free when the biggest party splits at least 20/80, because the Commons does not label them. | Reliable for whipped votes. Some conscience votes may slip through. |
| Subjects of votes and sectors of work | Keyword rules on division titles, job titles and employers. | Approximate groupings for comparison, not classifications. |
| Time to a first job after office | First ACOBA letter date against the end of the last post. | The letter date, not the start date. Only people who asked. |
| A minister's party | The party held at appointment, from the party spells of their seats. Later defections and loss of the whip are ignored. Peers who later sat as crossbenchers keep their earlier party. | The party they served under. |
3. What the data cannot tell you
- Why. We show what happens and how often, not why a minister was moved or a seat flipped.
- Ethnicity and similar traits. No reliable source exists at this scale, so we do not report them.
- Votes before 2016. No open source holds them in structured form.
- Anything not public. Undeclared donations, jobs that needed no clearance, private conversations.
4. Known issues
- Two 2025 appointments (Lucy Rigby and James Murray) have end dates before start dates in the source. They are two of 3,773 posts and move no figure visibly.
- Older-era comparisons carry more uncertainty, because Wikipedia and Wikidata are thinner for them.
- Figures since 2024 can change as people are ennobled, appointed or move on.
Ministerial ranks
- Prime Minister and Deputy. Head of government, and sometimes a deputy.
- Secretary of State. Heads a department. This rank and above is "the cabinet".
- Minister of State. Second rank, with a specific brief.
- Parliamentary Under-Secretary. The junior rank.
- Whips. Keep MPs and peers voting with the party. In government, but not in a department.
Found a mistake?
Use Report a correction in the footer of any page, with a source if you can. We check it against the record and fix it.