DP-008 establishes that a controlled vocabulary is a scope decision: the list of categories answers “what is this project about”, and a subject the list cannot express produces nothing rather than an argument. This is the operational half of that, and it points the other way.
When a document arrives with a real claim and no category to take, there are two available readings and they are not symmetric:
- The claim is out of scope. The vocabulary is right and the document is declined.
- The vocabulary is short a category. The document is in scope and the list has not caught up.
The first is the cheaper reading, it requires no work, and it is self- confirming: declining the document leaves the vocabulary looking complete, because the evidence that would have shown otherwise has just been turned away. Reading (2) costs a decision and some retagging, and it is the one that can be wrong in a way anybody notices.
So the default has to be (2). A claim the categories cannot express is evidence about the categories until someone shows otherwise, and showing otherwise means an argument about the kind of claim — not a shrug at the absence of a slot.
The failure this prevents is specific and it has a shape: the project reads its own filing convenience back as a statement about the world. It is especially quiet when the vocabulary is nearly right, because then only a few documents fall outside and each looks individually marginal. Counting is the antidote — if several documents are being declined for the same missing category, the category is missing.
Two tests worth applying before accepting reading (1):
- Would you decline this claim if it arrived with excellent evidence and a familiar author? If not, the objection was never about scope.
- Are the claims already in the record on this subject filed coherently? A subject scattered across four ill-fitting categories is a category that exists in the corpus and not in the list.
The corollary from DP-008 still binds: the vocabulary changes deliberately, by decision, and never by one entry quietly taking a tag that does not fit. This principle says which way to lean when writing that decision, not that the decision can be skipped.