usability

=**Usability**=

What is Usability?
Usability is a term used to measure how well a person can interact with a product or a system such as websites, cell phones (which I think are the worst to interact with), software applications or basically any device that you can interact with. Josephy Dumas and Janice (Ginny) Redish who are well known professionals in this field, have defined usability as "people who use the product can do so quickly and easily to accomplish their task." Overall, if you can learn and use a product to achieve your goals without killing yourself, then the people designing the product did a good job with usability testing and careful planning which includes user-centred design (refer to Tracy's wonderful definition).

What does usability measure?
There are five things that usability measures:

1. Ease of learning - How fast can you, who has never seen the user interface before, learn it sufficiently well to accomplish basic tasks? 2. Efficiency of use - Once you experienced and learned the system, how fast can you accomplish tasks? 3. Memorability - If you used the system before, can you remember enough to use it effectively the next time or you have to start over again learning everything? 4. Error frequency and severity - How often do you make errors while using the system, how serious are these errors, and how do you recover from these errors? 5. Subjective satisfaction - How much do you like using the system?

How is usability defined?
With the increase of technology, there is bound to be some bad interaction devices and that's why the ISO, International Organization for Standardization was created. These are international standards for 157 countries and there are two standards that further define usability and human-centred design:

1. "[Usability refers to] 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 user." - ISO 9241-11 2. "Human-centered design is characterized by: the active involvement of users and a clear understanding of user and task requirements; an appropriate allocation of function between users and technology; the iteration of design solutions; multi-disciplinary design." - ISO 13407

Conclusion
So, overall usability is an important part of design! But really, I think you can use the words interchangeably since good design should include effective usability. One example besides the horrible cell phones that I think are bad usability design are the Toronto parking meters. I'm sure I stood there for 10 or more minutes figuring it out in a sketching parking lot. Feel free to add to this or to tell about your stories about bad usability.

Some sites that will give the design nerds a laugh:

http://www.baddesigns.com/ (people complaining and giving suggestions to their problems on some products) http://www.slideshare.net/kosmar/real-bad-usability (image slide show of some bad designs) http://www.iallenkelhet.no/bad-usability-calendar-2007-is-here (these seem to be popular) http://www.noideasbutinthings.com/ixd/consols_and_control_panels/ (lots of controls)

Works Cited

"Usability.gov: your guide for developing usable & useful websites" Jan 9, 2008 <[|http://www.usability.gov/basics/whatusa.html]>

"Wikipedia: usability" Jan 9, 2008 

Added by Peter Ha