Now you're killing kittens.
There are two ways to measure usability.
You can use a black-and-white binary measure, where something is
either usable or not. To conduct the measure, you ask 'n' people to
perform tasks. If it crosses your acceptance threshold of success, you
have created something usable.
However, that's not a really useful measure, beyond it just basically
working. You have to get there first (something that only works for
people 25% of the time probably needs a lot of work). But, once you
get past the threshold, you're definitely not done.
That's when the scale comes in as the second measure. What makes
something "more usable"? First, you have to hunt down all the sources
of frustration and eliminate them. Once you've knocked them off, are
you done? There's probably ways to make something more usable by
increasing the delight -- reducing work flow, adding features,
creating experiences that make the user pleased and passionate about
the product/service/brand.
We can argue over semantics of whether something that isn't
frustrating has met basic use and therefore can't be more usable, but
I'm not sure there's value to that. In addition to saving the kittens,
avoiding that discussion has the advantage of helping teams focus on
what's important: creating a great experience. Who cares if the great
experience is coming because it's more usable or more enjoyable?
I didn't make this crap up. It's actually the work of Kano. You can
learn more about it here: http://tinyurl.com/65fv56
Or you can see this unfortunate rendition of it here: http://tinyurl.com/66qnfo
Hope this helps.
Jared
Jared M. Spool
User Interface Engineering
510 Turnpike St., Suite 102, North Andover, MA 01845
e: [EMAIL PROTECTED] p: +1 978 327 5561
http://uie.com Blog: http://uie.com/brainsparks
On May 30, 2008, at 12:42 PM, Robert Hoekman Jr wrote:
Usability is a scale from extreme frustration to extreme delight.
Been thinking about this statement. Is it really true? Isn't
"usability" only a measure of the degree to which something can used?
At the worst end of your continuum, "extreme frustration" doesn't
necessarily mean "unusable". Take the Word example, in which an
interaction was frustrating all the time, but because there was a
hack to get around the issue, ultimately, it was still usable.
Seems to me that frustration and delight are measures of
"enjoyability", not "usability". I think there's a difference, and
that the difference is important.
Yes, highly usable interactions do generally seem to be more
enjoyable, and less usable interactions do seem to be generally more
frustrating, but a less usable interaction doesn't have to mean
frustrating, and "frustrating" doesn't have to mean "less usable".
The two are not mutually exclusive.
-r-
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