Time and duration

Status: draft · Owner: Head of Design · Scope: every Aleris surface that states a time, a date, a duration or a wait · Version: v0.1 · Updated: 2026-09-13

Author: Torfinn Almers · Audience: writers, designers, developers, and the assistant/LLM layer

Supersedes: — · Related: [[constitutional/voice-is-the-present-expert]], [[constitutional/accessibility-is-foundational]], [[constant-and-contextual]], [[baseline/governance/time-display]]

Every surface that names a time makes two claims the writer did not intend to make: how well we know it, and how much it matters. "Your result is ready in 31 days" and "in about a month" are not two phrasings of one fact — they are two different promises, and a reader who counts can find one of them wrong. This page is the reasoning behind those choices. The formats, ladders and thresholds that follow from it are in baseline/governance/time-display.md; this page is why they are what they are.

1. What will the reader do with this time?

Precision shown equals precision needed, never precision available.

A system always knows the instant. It knows the appointment was created at 09:41:17 and that the referral is 19 days old. Almost none of that is what the reader came for. Someone deciding whether to leave the house needs "in 20 minutes". Someone deciding whether to worry needs to know whether a wait is normal. Someone auditing a record needs the instant, to the second, with the time zone attached.

Showing everything the system knows is not thoroughness; it is handing the reader the work of deciding what matters. The Present Expert has already done that work.

Test: What decision or action does this number serve? Show the resolution that decision needs.

Anti-pattern: The database timestamp. A precise instant printed because it was available, in a place where no reader acts on the seconds. Symptom: a patient-facing surface showing "2026-09-13 09:41:17".

Implication: Choose the unit from the reader's decision, not from the stored value.

2. Is "now" still true when this is read?

Relative time is a rendering, never a value.

"For två dagar sedan" is only correct if the moment of rendering and the moment of reading are the same, on the same clock. That holds on a live screen. It fails everywhere else: a cached page, an email, an SMS read the next morning, a PDF, a printout, a screenshot in a support ticket, a letter. In those places relative time is not imprecise — it is false.

This makes relative time a property of the display surface, never of the content. The value that is stored, sent, logged and printed is always the absolute instant; a surface may choose to render it relatively when the surface is live.

Test: If this is read tomorrow, or printed, is it still true?

Anti-pattern: Relative time outside a live surface. Symptom: "i morgon" in a letter, "för 3 timmar sedan" in an email, a countdown in a PDF.

Implication: Store and send absolute. Render relative only where the render and the read are the same moment, and only over a recoverable absolute value.

3. What does this granularity claim about our certainty?

Granularity is a claim about how well we know, and readers hear it whether or not we meant it.

People read a fine-grained unit as a statement that the speaker knows the thing precisely, and a coarse one as a hedge. This is not a matter of taste; it is measurable. The same estimate stated as "31 days" produced a confidence interval around 20 days wide, and as "1 month" around 25 days wide (Zhang & Schwarz, 2012). "1 år" and "12 månader" are the same duration and different promises.

The same finding carries the warning. The effect only exists for a source the reader considers reliable. A precise number that turns out wrong does not merely miss once — it removes the instrument for everything else we say afterwards, including the numbers we did know.

Test: Does the granularity we are showing match the certainty we actually have?

Anti-pattern: False precision. A number stated to the day when the underlying estimate is accurate to a fortnight. Symptom: an estimate that has to be revised in the next message.

Implication: Pick the unit from what we know, not from what sounds authoritative.

4. Do we control the thing we are being precise about?

Precision is a commitment. Only commit where we can keep it.

Where Aleris controls the thing — the appointment slot, the callback window, when a result is released, opening hours — precision is a promise we can keep, and vagueness reads as not having our own house in order. Be as precise as the reader can act on.

Where we do not control it — the position in a queue, a recovery time, when a referral is processed, a prognosis — precision is a promise we will break. Here the answer is not to be vaguer. It is to move the precision onto the uncertainty: say the typical case and say the tail. Medicine has already made this move for prognosis, from a single median to best case, typical case and worst case with their proportions attached (the Kiely scenario method). The striking finding is which failure dominates in practice: shown the full distribution, most clinicians will communicate it, but very few do so unprompted. The default error is collapsing to one number.

"Oftast 2–4 veckor, för några längre" is more specific than "några veckor", not less, and it commits to nothing we cannot keep.

Test: If this turns out wrong, will the reader experience a broken promise or a missed estimate? If the first, we were too precise about the value and not precise enough about the spread.

Anti-pattern: The lone point estimate for something we do not control. Symptom: a single number for a wait, with no typical range and no tail, that customer service later has to walk back.

Implication: Where we control it, state the value. Where we do not, state the distribution.

5. What does this granularity say about how much this matters?

Granularity also signals importance, so it has to be consistent to mean anything.

Alongside the certainty claim rides a second one: a fine unit tells the reader to care at that resolution. The two can point in opposite directions — we can be entirely certain about something trivial — so a rule that only handles certainty will still misdirect attention. Over-precision on a routine notice quietly elevates it; under-precision where precision is expected reads as carelessness, and in a clinical setting that is usually the more expensive of the two.

Two limits follow. Granularity only carries meaning against a baseline: if every surface is stamped to the minute, the minute says nothing and the signal is spent. And it is a weak signal next to placement, typography and repetition — it should not be asked to establish importance, only to avoid contradicting importance established elsewhere. The failure readers actually notice is the mismatch: a critical result stamped "för en stund sedan", a routine notice stamped to the second.

Test: Does the resolution here match the weight this item has everywhere else on the surface?

Anti-pattern: Granularity drift. A surface where the unit varies item by item for no reason the reader can see, or where two comparable items use different units ("3 veckor" on one card, "21 dagar" on the next).

Implication: Set a default granularity per surface and deviate deliberately. One granularity within any set the reader compares.

The gate

One question decides the unit in most real cases:

Could the reader check this against a calendar and find us wrong?

If they can, do not round into a coarser unit. Six days is "6 dagar", not "1 vecka" — the reader counts, finds six, and now discounts every other number on the page. A coarser unit is honest at an exact multiple, or with an explicit hedge ("ungefär tre veckor"), and nowhere else.

Origin

Harvest provenance: Research pass and dialogue, 2026-09-11 to 2026-09-13 (session research document tidsvisning-research.md, prep). The attention-management framing — that over-precision wrongly elevates a subject while under-precision reads as unprofessional, asymmetrically so in a clinical setting — is Torfinn's and is the reason §5 exists as its own principle rather than a note under §3. No Aleris surface audit has been run yet; that is the first Open item.

External lineage: Zhang & Schwarz (2012), How and Why 1 Year Differs from 365 Days, Journal of Consumer Research 39(2) — the granularity/certainty finding in §3, including the expertise and trustworthiness conditions. Lewis & Oyserman (2015), When Does the Future Begin?, Psychological Science — fine-grained units and action on distant goals. Pandelaere, Briers & Lembregts (2011), The Unit Effect, JCR 38(2) — perceived magnitude. Krifka (2007), Approximate Interpretations of Number Words — round numbers read on a coarser scale, the linguistic half of §3 and the gate. The scenario method in §4 from the cancer-prognosis communication literature (Kiely et al.; see "The median isn't the message", 2022). Convention sources for the formats, not for the reasoning: GitLab Pajamas (absolute by default), AWS Cloudscape (relative by default) — two careful systems that contradict each other, which is the evidence that the format question is convention rather than settled.

Open

The relevance inference in §5 is sound as a mechanism and untested in interfaces. The pragmatics literature supports that readers draw conclusions from over-specification; none of it measures the effect in a UI, and no study was found comparing "om 4 veckor" with "om 28 dagar" in a care context. Choosing to act on it anyway costs little; treating its magnitude as known would be wrong. A small test on a waiting-time surface would close it.
Whether the weekday step in the past-event ladder earns its place in Swedish. The ladder in baseline/governance/time-display.md shows a weekday name for 2–6 days back, on the reasoning that a reader can place a weekday on a calendar without counting. Whether Swedish readers prefer the date immediately is unknown. Closed by a preference test, or by dropping the step if it complicates implementation more than it helps.
How this interacts with clinically owned wording. Care instructions that state intervals ("ta tabletten var åttonde timme") are clinical substance, not form, and sit outside the voice scope. Where the boundary runs — an appointment interval in a treatment plan, say — is not decided here.

[[constitutional/voice-is-the-present-expert]] — the stance this reasons from; a time stated from the organisation's perspective fails there first
[[constitutional/accessibility-is-foundational]] — the floors the markup rules in Baseline serve
[[constant-and-contextual]] — why the ladders differ between communicative and instrumental surfaces
[[baseline/governance/time-display]] — the formats, ladders and thresholds this page governs
[[patterns/chat-response-simple]] — the existing rule that a time or date in a chat answer is written out in plain text