The BBC News has an interesting article on its website—“Hamburger icon: How these three lines mystify most people”—that has some really good info in it. In particular, this struck my eye:

“I did multiple tests,” says James Foster, a web developer based in New Zealand, who has surveyed users’ interactions with the button over the course of many months. “The results all came out the same - the icon is not as clear to some users as developers and designers think it is.”

Adding the word “menu” underneath the three lines increases the button’s use by 7.2%, according to Foster’s tests.

Putting the hamburger inside a box, so it looks like a button, increases use by 22.4%.

Switching the lines for the word “menu” makes 20% more people click, Foster found.

Now, there are obviously some problems with the numbers here—increased it 7.2% from what? 80%? 2%?—but I still find this useful, & it jibes with other things I’ve read & seen. Just knowing that certain design patterns increase usability is useful to know.