Hey, designer. I know screen real estate on mobile is extremely limited. I know it would be really nice to fill the whole screen with content and just have a little, square, "more" icon tucked in the corner. I know you've tried to establish the hamburger icon as the universal "more" icon.
Too bad. Users aren't catching on as quickly as you'd like. They don't notice, understand or utilize the icon. Even if they do notice and understand, an ambiguous "more" is dramatically less engaging than explicitly showing what they can get. A "more" icon is asking them to expend effort up front exploring your interface with no clear reward in sight. So, they don't bother. Like, a measurable 50+% drop in engagement don't bother.
So, stick to tab bars as much as you can. It seems like a waste of screen space. But, the results still seem worth the cost.
- Most users do understand the hamburger icon, so they notice and understand it, but they definitely don't utilize it.
- It's not really about engagement. Users generally don't go about thinking to themselves "boy that icon looks so engaging and just begs for a click!"
- It's all about workflows and hints built into these workflows.
At any moment on your website/app your users are trying to accomplish something. UI nudges and pulls them in the correct direction towards their destination. At every step the user is evaluating the screen to determine the thing most relevant to moving closer to their goal.
A hamburger button never - and I mean never - tells the user "click me and you'll be closer to your goal!". A hamburger button is utterly neutral in every single way, even to the trained user who knows what a hamburger button does.
- When evaluating the screen to determine what they should do next, almost everything feels more relevant than the hamburger button.
It's not that people don't want to click on the hamburger button, it's that in any particular circumstance some other UI element will feel more relevant (even if it isn't actually true).
It probably isn't helped by the superflat UIs that are the current fad that make it impossible to tell what elements are active or what they do.
It's the kind of thing that makes sense on phones because the screen space is so precious (although with modern phones this is becoming less and less true), but only because you're willing to trade off some usability for getting more content on the screen. For a desktop site or application where you are not space constrained it is just bad design.