Checking a document's claims

#Numbers the author works out

Every number the canvas does not compute — a worked example's arithmetic, a step count, a trace through an algorithm, the readings a plot is drawn from — is worked out before it is written. A plausible number and a derived one look the same on the page, and the reader has no way to tell them apart, so the burden sits with the author.

#Output quoted from a run

A code environment's output is authored, not executed, so the line stating what an interpreter prints is quoted from a run that happened. In a runnable environment the reader can compare the authored output with the real one in one click.

#Facts checked or cut

Historical claims, attributions and named results are checked against a source, or they come out of the document. Hedging an unchecked claim — often attributed to, is said to — keeps the assertion and drops the accountability for it.

Values quoted from the world are looked up rather than recalled. A coordinate on a region environment written from memory puts a marker in the sea, and a compiling document displays it as confidently as a right one.

#The data a plot is drawn from

A dataset is read before the prose describes it. The narrative's claims about a plot are claims about these rows, and an author can make them only about rows they have seen — a plot of unread data leaves the prose with nothing but generic captions, notice any outliers…. The attached file is the data itself, not a rounded or trimmed excerpt, so a reader checking a number against it finds the same number.

#cite and the reference list

A source the document draws on is declared with cite beside the scenes and pointed at from the prose with !cite, with locator: saying where in the source the claim is. A citation of a source the document does not declare is refused as an unknown id.

cite#fs1969(
    authors: Fellegi, I. P. and Sunter, A. B.
    year: 1969
    title: A theory for record linkage
    container: Journal of the American Statistical Association
    pages: 64(328), 1183–1210
    doi: 10.1080/01621459.1969.10501049
)

scene{
    The comparison vector and the likelihood ratio built from it are
    Fellegi and Sunter's !cite:#fs1969(locator: p. 1187), and the
    decision rule follows from them directly.
}

A figure taken from a paper, a dataset with an origin and a result quoted rather than derived each carry a citation, because the reader cannot check any of them from the document itself.