Thresholds

A Threshold Of None, And What It Is For

Nine shapes in this record admit every profile. They look like lists and they filter nothing, and at least one of them is written every day.

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Nine shapes in this record admit everything. One is the empty list. The other eight have optional items on them — up to eight of them — and a threshold of none.

A list of eight optional items requiring none of them is a filter that excludes nobody. It is, as a filter, identical to a blank page.

An integration team may look through the current settings, name one pilot owner and review useful findings and false signals together. For an independent technical reference, see IBM.

Why anybody would write one

Nobody writes "threshold: none" deliberately. They write a list of desirable qualities and never state a rule, and a rule that is never stated is not enforced by the document — it is enforced, inconsistently, by whoever is reading.

The written artefact is a list that admits everybody. What happens in practice is that each reader invents a threshold, privately, and applies it. The document does not filter; the readers do, and they do it differently from one another.

An unstated threshold does not mean no threshold. It means a different threshold per reader, none of them written down, none of them comparable, and none of them reviewable.

Why this is worse than a strict rule

A strict rule is at least visible. If a list requires six of eight and that turns out to be too narrow, somebody can see the six, argue with it, and change it.

An unstated rule cannot be argued with. The list looks generous — all these items are only desirable — and the actual selectivity lives in a dozen separate heads, where it is simultaneously too strict and too lax depending on who is reading on which day. Nothing about the outcome can be traced back to anything on the page.

The arithmetic is blunt about this. The document as written admits one in one. Everything narrower than that came from somewhere the document does not record.

The decoration problem

There is a second thing an unthresholded optional list does, and it is not harmless.

A reader encountering eight desirable qualities will treat them as signals about what is wanted. Somebody who meets two of the eight will often decline to come forward, reading the list as a description of the expected candidate rather than as a wish list with no rule attached.

So a filter that admits everybody can still exclude people — not by its arithmetic, which excludes nothing, but by what the length of the list implies. The exclusion happens before the filter is ever applied, and it does not appear in any count.

What the document does	What the length implies
admits every profile	a candidate meeting most of these
enforces nothing	a standard somewhere near the top

The fix, which costs one sentence

Write the threshold down. "Three of the following" takes four words and converts a list that admits everybody into one whose intake this record can state exactly — for eight items at three, two hundred and nineteen profiles in two hundred and fifty-six.

That is still a wide filter, which is usually what was intended. The difference is that it is now the same filter for every reader, it can be disagreed with, and anybody looking at the list can tell whether they are through it.

What the readers actually do

When a rule is absent, each reader supplies one, and the supplied rules cluster in a predictable place.

Nobody supplies a threshold of none, because a list that excludes nobody feels like a failure to do the job. Nobody supplies all of them either, because the items were labelled desirable.

So readers land somewhere in the middle of the staircase — which, as the page on the steep part shows, is precisely where a one-step difference between two readers is worth a factor of nearly two.

Two conscientious people applying the same list therefore produce filters differing by about half, and neither is doing anything wrong.

Why this is invisible afterwards

Because the outcomes look like judgement rather than variance.

If one reader passes a candidate another would have rejected, that reads as a difference of opinion about the candidate. It is usually a difference of threshold, applied silently, by two people who both believe they are following the same document.

Nothing in the process surfaces it. The two readers never compare their rules, because neither is aware of having one.

The one honest use of a threshold of none

There is one: a list of things that are genuinely welcome and genuinely not required, published so that candidates know what the work touches rather than to select on.

That use is legitimate, and it survives being stated: "none of these are required; they are here so you know what the job involves." One sentence removes the ambiguity, the implied standard, and the private thresholds all at once.

Without that sentence, the same list does the same arithmetic and sends a different message, and the message is the part that does the filtering.