Do position dots under a carousel need to be clickable?

Question

It is common convention to make position dots under carousels (as shown on Apple's site below) clickable.

My question is: is this convention based in any user research, or any experience of user responding badly to non-clickable dots?

I have two reasons for challenging this convention.

1. Given that these dots give no indication of what content is on which "page" of the carousel, there is no information-seeking objective that can be satisfied by them (unlike a "sort and jump" strategy with e.g. alphabetical pagination)
2. They are almost always too small to hit on a touch-based device, and so have diminishing usability in themselves

Does anyone have any personal experience or research to confirm / disconfirm their usefulness?

(Please don't refer me to sites where this is used, unless you were involved in the design/evaluation of those sites. I understand this is widely adopted convention. What I want help with is evaluating this convention, not recognizing it as a convention.)

Answer 1

Perhaps it's worth coming at this from the other angle. You might ask yourself two questions to help answer this problem.

The first is: do those links reduce usability in any way? From a usability perspective, they're entirely discoverable given that the primary purpose of the dots are to afford the carousel mechanism itself. Given that, I can't think of a reason why you wouldn't want them to be a control, so the answer to this is probably not.

The second is: what's the alternative? (Also, what benefits does a potential alternative provide?) The alternative presumably is no links at all, though keeping the indicators. Does having a plain indicator provide any special usability benefit? Probably not.

Given that there appear to be no costs (or opportunity costs) to having these links, then they can only increase usability, and improve the user experience. Obviously if you have different circumstances which make these links a cost in some way, then you will need to weigh up the costs and benefits and make a decision based on the balance of the two.

Answer 2

I can't offer research, just views! I would consider that touchscreen users are not the only users of websites - I find it easy to click these dots with my mouse. Also, while the dots don't offer any cues for the information they contain, they are typically on a carousel with a rotation of (say) 5 seconds, so I will sometimes want to move onto the next screen out of a sense of curiosity, and I'd probably feel frustrated if I couldn't do that.