# One-page claim-typing guide

Every claim in the brief is labelled with exactly one type before it enters the
table. The type tells the reader how much weight the claim can bear and what would
change it. When a claim could fit two types, pick the weaker one and say why in
the confidence or uncertainties.

## The four types

**fact** — Something a source states as having happened or been measured.
- Test: could you point to the sentence in a source that asserts it?
- Example: "Absence fell from 6.2% to 4.1% over the pilot" (the pilot report says so).
- A fact is only as good as its source; a fact from a single unaudited source is
  still a fact, but its *confidence* should reflect that.

**estimate** — A projection, forecast, approximation, or figure derived by
arithmetic on supplied numbers.
- Test: is it about the future, or a rough quantity, or a number you computed
  rather than read?
- Example: "Throughput held at roughly 95% of baseline" (the team lead's estimate),
  or "£6/user/month × 12 = £72/month" (arithmetic on supplied figures).
- Arithmetic on supplied figures is an estimate, not a new fact — label it so.

**opinion** — A judgement, preference, or evaluation attributed to a person.
- Test: is it a "should", a "better", a "my view" — something a reasonable person
  could disagree with while accepting the facts?
- Example: "The change would help retain staff" (the manager's view).
- Attribute the opinion to whoever holds it; an unattributed opinion is the
  agent's own and must be marked as unverified reasoning, not sourced.

**assumption** — A premise the reasoning depends on that the sources do not
themselves establish.
- Test: if this turned out false, would the conclusion fall? And do the sources
  actually show it is true?
- Example: "Headcount stays constant" — the memo relies on it but does not prove it.
- Surface assumptions explicitly; a hidden assumption is how a brief misleads
  while every stated claim is individually true.

## Deciding between types

| If the claim is... | ...it is a |
|---|---|
| Asserted as measured or occurred, in a source | fact |
| About the future, approximate, or computed | estimate |
| A judgement someone holds | opinion |
| A premise the sources leave unproven | assumption |

## Confidence is separate from type

Type says *what kind* of claim it is; confidence says *how firmly the sources
support it*. A fact from one unaudited source may be `medium`; an estimate
corroborated by two sources may be `high`. Never let a confident tone stand in for
a source — if the sources are thin, say so in the confidence and the uncertainties.
