Limits

A Filter Is Not A Description

A list of requirements is asked to describe the work and to select among candidates. The two jobs pull opposite ways, and the arithmetic shows how far.

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A list of requirements is usually written to do two things.

Describe the work, so that a reader understands what the job involves. For that, longer is better: more items means more information.

Select among candidates, by excluding those who do not qualify. For that, every item is a halving or a contribution to a threshold.

The method is easier to evaluate when reviewers explore the analytics options and document a baseline before changing any settings. For an independent technical reference, see GitLab.

The two jobs pull against each other, and most of the trouble in this record comes from one document being asked to do both without anybody noticing they are different jobs.

Where the conflict shows

A writer wanting to describe thoroughly adds items. Under a fixed threshold that widens the filter, as the page on adding optional items shows — so the description improves and the selection loosens.

A writer wanting to select tightly adds compulsory items or raises the threshold. Both narrow the filter and neither adds information, since the items were already listed.

So the two goals do not merely compete for space. They move the same parameters in opposite directions.

Goal	Move	Effect on the other goal
describe better	add optional items	filter loosens
select harder	raise threshold	nothing described
select harder	promote an item	filter narrows sharply, nothing added

The resolution the arithmetic offers

Separate the parameters, which the record shows can be done cleanly.

The items carry the description. Add as many as are genuinely useful; a reader learns from each one.

The rule carries the selection. Set it to the intake the work needs, independently of how many items there are.

Because adding items widens the filter at a fixed threshold, a list can be lengthened for descriptive purposes and the threshold raised to compensate — landing back at the same intake with more information on the page. That combination is available at every length and it is the only move in this record that improves both goals at once.

The items say what the work is. The rule says how much of it is required. Written separately they cooperate; written together they fight, and the fight is invisible.

What happens when they are not separated

The document drifts towards selection, because selection is the parameter that gets adjusted in meetings and description is the one that gets assumed.

The result is the shape this record keeps returning to: a long list, every item treated as compulsory by default, admitting one profile in two hundred and fifty-six, which nobody chose and which describes the work no better than a shorter list would.

The two-document version, worked

Separating the jobs is cheap, and the arithmetic shows what it buys.

The describing document carries everything the work touches, at whatever length is useful, with no rule attached and an explicit sentence saying none of it is a requirement. It filters nothing, which is the point: its intake is one in one.

The selecting document carries only what is actually being selected on. Three compulsory items and a stated threshold over four optional ones, say, which admits a figure anybody can compute in under a minute.

Document	Length	Intake
describes the work	as long as useful	1/1
selects	as short as honest	computed and stated

Neither document is harmed by the other's existence. The long one informs without deterring, because it says it is not a filter; the short one selects without being read as a description, because it is not one.

Why one document cannot do both

Because the two jobs want opposite lengths.

Describing wants length: more detail, more of what the work involves, more for a reader to recognise themselves in. Selecting wants brevity, because every line in a selecting document is a line somebody will be excluded by, and a line that nobody is excluded by should not be in it.

A single document resolves that tension by compromising both — it is too short to describe properly and too long to select honestly — and then the compromise gets hidden under a word like "preferred", which lets a line sit in the document without anybody deciding which job it is doing.

What the arithmetic cannot settle

Which intake is right. That depends on the work, on how many candidates there are, on what happens if the post goes unfilled, and on a dozen things the record has no access to.

It also cannot say what belongs on the list at all. Deciding that an item describes the work is a judgement about the work.

What it can do is hold the two jobs apart long enough for each to be decided on its own terms — which, given that they are usually decided together and by accident, is most of the value on offer.