Why icon consistency is harder than it looks

Streamline wrote a nice essay on icon consistency. Making the thousandth icon look like it came from the same hand is hard, no argument. Whether users care is another question.

Even they say that when consistency and legibility clash, they pick legibility. So consistency is a means, not the goal. The essay has no user data I could find. And Streamline sells icon libraries, so "a big set is very hard" is a handy message. That's my read.

Nielsen Norman Group tested a clock icon for browsing history. One test, but a good one. People knew it was a clock. Not one participant clicked it. Their advice: add a text label. A perfectly consistent set nobody can read still failed.

So ask if the thousandth icon belongs in the set. Then ask if anyone recognizes it.