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Visibility of System State

STR·05 · 5 of 11

The interface must keep the human's model and the machine's state in agreement, continuously and legibly.

documented A named, findable source says this. Why: One of Nielsen’s ten heuristics, published and stable since 1994.

The same task, built twice

Both panes below are real interfaces. They respond, they can be got wrong, and each is timed from your first move in it. The times are not a study — two panes, one reader, no controls. They are here to make a difference you can feel into a number you can see, and nothing is recorded or sent anywhere.

Your task

Step through all five states with the buttons. Decide, in each one, what you would do next.

One blank—

Your documents

Four of the five render identically: an empty box. Loading, empty, failed and offline are four different situations with four different correct responses, and this interface cannot tell you which one you are in.

Five answers—

Your documents

Each state says what happened and what to do. Note that the empty state is not an error and does not apologise — it is a working system with nothing in it yet, and it offers the action that fixes that.

What to watch On the left, press Error then Empty. Nothing changes. A user in that position will wait, then reload, then blame themselves — three wrong moves, all caused by an interface that declined to say which of four things had happened.

The principle

OriginNielsen's first heuristic (1994); Norman's gulf of evaluation (1986/1988) is the deeper statement.
EvidenceIts violations fill the basement: every mode error is this principle, unpaid.
Limits & misuseVisibility is not verbosity — a system narrating everything buries the one state change that mattered. The skill is salience proportional to consequence.