Working memory holds a small number of chunks, so the design lever is what counts as a chunk, not the raw item count.
LAW·004
I'm designing
A Form
Signup, application, settings or anything else where people type things in.
What this surface turns on
- Which fields you genuinely need, and what consumes each one.
- When to validate, and what happens on failure.
- Whether the flow is one page or several steps, and whether progress survives leaving.
- How much messy input you accept before rejecting it.
Where these usually go wrong
- Placeholder text used instead of a label, which disappears the moment someone types.
- Validation that judges a half-typed value.
- Entered data lost on validation failure or back navigation.
- Over-strict format rules that reject valid international input.
- Fields nobody consumes, kept because removing them was never anyone's job.
Why these
Forms fail on three things: what you ask for, when you tell people they got it wrong, and what survives when they leave. These entries are grouped around those three, which is why validation, error writing and multi-step patterns appear together here rather than in their usual shelves.
Why it works the way it does
The reasoning layer. Read these when a decision needs justifying, or when something is failing and you cannot say why.
Decision time grows logarithmically with the number of equally likely choices, so the tenth option costs far less than the second.
LAW·001
Be liberal in what you accept and conservative in what you send, which for interfaces means accepting messy input and returning clean output.
LAW·012
Every system has irreducible complexity. The only question is whether the user absorbs it or the product does.
LAW·005
Work expands to fill the time available, which is why open-ended tasks in an interface tend to sprawl.
LAW·013
Unfinished tasks stay mentally active, which is why visible progress pulls people back to complete them.
LAW·010
The craft decisions
The visual and structural foundations that carry most of the weight on this surface.
Things placed close together are read as belonging together, before anything is read.
FND·004
Shared edges create invisible lines that organise a layout and make it feel deliberate.
FND·003
A fixed set of spacing values, so every gap in the product comes from the same vocabulary.
FND·042
Empty space is a design element that groups, emphasises and sets pace, not leftover area.
FND·015
Using size, weight, colour and space to make the structure of text visible before it is read.
FND·032
Difference is what makes anything perceivable, and it is measurable for text against its background.
FND·002
Patterns to reach for
Solutions people already recognise, with the conditions under which each one earns its place.
Checking input at the right moment, which is rarely while the user is still typing.
PAT·007
Breaking a long task into steps, which reduces per-screen load but adds navigation cost and abandonment points.
PAT·016
Suggestions as the user types, which turns recall into recognition when it is fast enough.
PAT·003
The screen before there is anything to show, which is a teaching opportunity rather than a gap.
PAT·010
Reversing the last action, which is the single highest-value safety mechanism in most products.
PAT·022
Components you will specify
Each entry covers the states, behaviour and accessibility contract you need to define.
Free-form entry, where the label, the hint and the error placement do most of the work.
CMP·003
Choosing one option from a known set, which is the wrong control below about five options.
CMP·004
One of the hardest components to get right, and one where typing is often faster than picking.
CMP·009
Accessibility requirements
Not a separate pass. These are the requirements this surface raises, mapped to the decisions that produce them.
Every input needs a persistent label, and format requirements must be stated before the user types.
A11Y·017
Errors must be identified in text, described specifically, and accompanied by a suggested fix where one is known.
A11Y·016
Everything must be operable with a keyboard alone, which is the single most load-bearing accessibility requirement.
A11Y·002
The visible marker showing where keyboard focus is, which must never be removed.
A11Y·003
Telling assistive technology that something changed, when focus did not move to say so.
A11Y·009
Language and content
The words do more work here than most teams budget for.
The small pieces of text that do most of the work: labels, hints, empty states, errors and confirmations.
WRT·001
Say what happened, why if you know, and what to do next, in that order and in plain language.
WRT·002
Writing that does not exclude, misgender or make assumptions about the person reading it.
WRT·005
Designing so the product can be adapted to other languages and regions without being rebuilt.
WRT·006
How to find out
Research methods suited to the questions this surface raises.
Watching people attempt real tasks, which is the most direct evidence available about whether a design works.
RES·001
Measuring progression through a sequence, where the largest drop is rarely the biggest opportunity.
RES·011
Measuring where people click first, which predicts task success better than almost any other single measure.
RES·007
Check your work
Interactive checklists, with progress saved in your browser.
A review pass for any form, covering structure, labelling, validation, errors and accessibility.
CHK·001
A practical WCAG 2.2 AA review pass, ordered so the checks that find the most problems come first.
CHK·002
Documents you might need
Fillable templates, prefilled so they are usable rather than empty.
Every path through a task, including the error paths and the states most flows forget.
TPL·005
A feature specification that covers states, edge cases and accessibility rather than only the happy path.
TPL·011
Decisions other teams made
Worked cases, including the options that were rejected and why.
Splitting a long form into steps did not raise completion until the team also saved progress and let people come back.
CASE·009
A retailer required registration before purchase to build its customer database, and lost the sales it was trying to capture data about.
CASE·001
Designing something else?
Neighbouring territory. Each surface reuses much of the same material, arranged around the decisions that surface turns on.