Chain of evidence

The case

Every chain begins with a claim stated precisely enough to be wrong, and a threshold — the confidence at which you would act on it.

Stating the threshold first is the discipline. Deciding what would convince you after you have looked at the evidence is how everybody rationalises, including people who are right.

The links

Each link is one step in the argument, and carries:

statement — what this link asserts. One claim, not a paragraph.

status — have or missing.

source — for links you have. Something a stranger can check.

strength — 0 to 1: how much this link actually contributes to the chain.

reason — for links you are missing: classified, suppressed, blocked, or unknown.

note — anything a reader needs to interpret it.

Strength is not enthusiasm

The field people get wrong. Strength is how much work this link does in the argument, not how much you like it or how well sourced it is.

A perfectly sourced link that everybody already agrees on has low strength — it is not what the conclusion turns on. A weaker link that is the only thing distinguishing your hypothesis from the alternative has high strength, and if it is the one that is missing, that is the most important fact about your chain.

The conclusion

Computed from the strength of what you have, weighed against the explained weight of what is missing. It reports whether a conclusion is reached, at what confidence, and a summary in the form the charter asks for: here is what we know, here is what is missing, here is the conclusion.

A half-built chain is valid

Everything except the case id defaults. You can write the claim and two links today and come back. A tool that demands a finished argument only ever receives arguments people had already finished having.

Two homes, one shape

The same structure is used as a standalone case and as the evidence block inside a decision. Same fields, same arithmetic, same rendering. A chain you built standalone can be the chain a decision rests on without being rewritten.