What is usability?
Usability seeks to make products easier to use.
Usability is critical to user-centred design. When users are interacting easily with a user interface, they hardly notice it is there, the interface almost disappears - external link, concentrating fully on their goal. And a website
is not really accessible if it is not also usable, as usability expert and author Ginny Redish - external link puts it.
Usable systems are designed around human capabilities and limitations
Usability rules the web. We’re making vast amounts of data available online at an astonishing rate and have more choice than ever. There is real competition for users’ time and attention. With such overwhelming choice – if users can’t figure out a website quickly – they leave.
What it means for something to be usable
Usability helps users perform their tasks.
According to ISO 9241, Part 11, usability is
the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use.
Usability is defined by five quality components:*
- Easy to learn – how easy is it for users to accomplish basic tasks?
- Efficient to use – once users have learned the design, how quickly can they perform tasks?
- Easy to remember – when users return to a design, can they remember how to use it?
- Few errors – how many errors do users make, can they easily recover from them?
- Satisfaction – how pleasant is the design to use?
To help improve your product and understand your users better, the only way is to observe them.
We often receive criticism that our homepages are too busy. The fact is that a useful homepage should be busy. By that we mean that there should be snippets of real content and links to the various things that the website provides; having more things will make it appear busier.
Ginny Redish, usability expert and author, outlines the purpose of homepages in her book Letting Go of the Words: Writing Web Content That Works - external link
Five major functions of homepages, page 29:
- Identifying the site, establishing the brand
- Setting the tone and personality of the site
- Helping people get a sense of what the site is all about
- A useful home page makes it instantly clear what the site is about
- A useful home page is mostly links and short descriptions
- Letting people start key tasks immediately
- Sending each person on the right way, effectively and efficiently
- Use your site visitors’ words
- Don’t make people wonder which link to click on
Useful homepage usability resources
- Jacob Nielsen’s 113 Design Guidelines for Homepage Usability - external link
- UIE’s Usability Tools Podcast – Home Page Design - external link
Why we don’t use drop-down menus
The usability of drop-down menus is always a hot topic of debate. To many, they’re the panacea for a website’s navigation. Our experience is that drop-down menus cause usability issues and they don’t scale well on small screen devices like smartphones, which need even simpler navigation to be usable.
Drop-down menus are not all bad though - external link. Most of our software applications use them. And for large websites, with lots of information to navigate, sometimes they’re the best option. What we don’t realise though is that on the Web our audience is quite diverse: some are experts and others not, some young and some not so young – not everyone is equally competent at the dexterity and cognitive capacity required to effectively navigate using drop-down menus. But those aren’t the only usability problems.
Two research reports out of User Interface Engineering reveal how we navigate the web; when viewed together, they show why drop-down menus can cause usability issues:
- The Right Trigger Words - external link, 15 November 2004
- Ultimately, users are looking for trigger words on your site.
- Users Decide First; Move Second - external link, 25 October 2001
- Users decide what they are going to click on before they move the mouse.