Redundant Status Cues

Colour is the case everyone knows: WCAG SC 1.4.1 Use of Color, which the Rams review files as a Serious accessibility failure. Roughly 8% of men have some colour vision deficiency — but colour-only status also fails on monochrome displays, in bright sun, and on a printout, so the audience is far wider than the one people picture. The general rule is bigger than colour, though, and it is WCAG SC 1.3.3 Sensory Characteristics: no single sensory channel may carry meaning on its own.

Colour is one channel. So is SOUND (an error chime with no on-screen message — see interactions-sound-not-sole-channel), SHAPE ("click the round button"), SIZE, and POSITION ("the panel on the right", "see the box below"), each of which means nothing to a screen reader user, and position means nothing to anyone on a narrow viewport where your two columns just became one.

Test it by asking what survives if the channel is removed: greyscale the screen, mute the audio, read the DOM order aloud. Whatever is left must still identify the thing. Always carry the meaning on a second channel: an icon or glyph beside the status colour, a text label on the badge, an underline on the link, a pattern or a direct label on a chart series, a visible message beside the sound, a name beside the "round button". Green alone is not success; green with a checkmark and the word "Success" is.