Ah, I meant with regard to age. If the sample is 8, say, in 99.9% of
cases, age won't matter. Just get a mix of participants who do and are
motivated to do what you're interested in observing.
If you're testing 30 or 50 or 100 participants, you might want to pay
attention to make sure you have participants from all the age ranges
you care about, but you shouldn't be selecting or screening on age as
long as they do and are motivated to do the same kinds of tasks with
your designs.
Most demographics don't matter in usability testing, most of the time.
(Of course, there are exceptions.) Why? Because the purpose of
usability testing is not to generalize preferences to a larger
audience but instead to identify problems with a design that cause
frustration and confusion. If one or two participants in your mix have
the issue, you want to fix that because you don't want *anyone* to
have it.
Dana
On Mar 12, 2009, at 10:21 AM, James Page wrote:
@dana
I am bit confused here by your question "What difference does it
make how many you're testing?"
Surely factors such as "margin of error", and "statistical power"
are important, or are they not?
The point of testing is to find out if your wrong, or right. How do
you know if your wrong or right based on a small sample.
@jenrandolph
On remote usability testing we get more behavioural differences by
machine configuration, then by age. What I mean by machine
configuration is manufacture and screen size. Mac users are
different, why - I don't know. And we get allot of behavioural
differences by culture - (place of birth vs residence). Also
environment seams to have quite a large impact. People in the lab,
and at home spend more time to trying to complete a task before
giving up, then people at work. This is of course impacts success/
failure rates.
We are doing more research here.
James
http://blog.feralabs.com
2009/3/12 Dana Chisnell <[email protected]>
What difference does it make how many you're testing? By breaking
the sample into groups, you're just creating extra work. Are you
going to compare the data by age group? Why would you do that? The
only reason I can think of is if you're creating different sites.
You're not.
Dana
On Mar 12, 2009, at 9:21 AM, James Page wrote:
Out of interest how many participants are you testing with? Could
you break the numbers down?
James
http://blog.feralabs.com
2009/3/12 Dana Chisnell <[email protected]>
Thanks for the prompt, Jared. There's no reason to limit the age
range *at all.* As long as the behaviors are the same -- that is,
the task goals of the users -- across age ranges, then it doesn't
matter a bit how old the participants are.
As members of UPA, people over 65 would very likely have the same
tasks and goals in mind as someone younger: Maintain membership
information, renew memberships, find out what's going on in the
association, get in the consulting directory, find out who is on
the board, find out where the conference is, etc.
Limiting the age range wouldn't benefit the research. In fact,
limiting may be a detriment.
Dana
:: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: ::
Dana Chisnell
desk: 415.392.0776
mobile: 415.519.1148
dana AT usabilityworks DOT net
www.usabilityworks.net
http://usabilitytestinghowto.blogspot.com/
On Mar 12, 2009, at 12:04 AM, Jared Spool wrote:
So? Why limit the age range? How does that benefit the research?
On Mar 11, 2009, at 10:20 PM, Todd Zaki Warfel wrote:
Perhaps because the core audience isn't older than 65? Not to say
that there aren't any, but I'd imagine, based on the meetings and
conferences that I've been to, that the number of people over 65
are statistically quite small.
On Mar 11, 2009, at 11:54 AM, Dana Chisnell wrote:
May I ask why the age range limits to 65?
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