On Mar 12, 2009, at 10:07 AM, Todd Zaki Warfel wrote:
The key question is: How do you know that people older than 65 will
behave differently than people younger than 65?
My thoughts exactly. I don't see how you would know this until
you've actually done some research and testing on it. If you know
that your audience doesn't really have people over 65, then there's
no reason to recruit them. If you know you do, then you should
recruit them, even if it's a small number "somewhat" proportionate
to the percentage that 65 and over make up in your group.
If you're recruiting from communities that are part of your target
audience, then it would be difficult to recruit people outside your
target audience. If you're not recruiting from communities that are
part of your target audience, there's probably something terribly
wrong with your recruitment sourcing strategy.
I say somewhat, because if you recruit 20 participants and 65 and
over only represent 2% of your population, you'd recruit less than 1
participant. In a case like this, we'd typically recruit 2-3 so we'd
have enough to see if there's a significant difference that would
warrant additional research on that smaller group.
Again, if you're recruiting from communities that are part of your
target audience, it would be hard to dramatically over-represent a
group through pure random selection. (If you're picking out of a bag
of 1,000 marbles where 20 of them are blue, it's unlikely you'll pick
all 20 in the first round.)
Leave it to chance, I say. Hopefully, you're not doing only one round
of testing and therefore any problems that arise from recruitment
skewing in the early rounds can be compensated for in later rounds.
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 Twitter: jmspool
UIE Web App Summit, 4/19-4/22: http://webappsummit.com
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