On Jul 14, 2008, at 2:58 AM, Elizabeth Parham wrote:
I have to do a proposal including timings for a solution in which
there will
be 300 end users of a new system aimed at improving efficiency in
the work
place by using technology where before things were done on paper or
over the
phone.
What percentage of these 300 do I need to observe in their place of
work,
interview and so on for the information to be representative of the
whole?
- I want to get enough information to be able to develop personas and
wondered if there were guidelines regarding the numbers and
statistics for
getting it right.
Hi Elizabeth,
The answer is quite simple. It's very easy to calculate how many folks
to observe and interview to ensure you've learned everything you need
to learn.
The only problem is, you can't make the calculation until you've
already done all the observations and interviews. You just don't have
the necessary information to do the calculation. :)
Short of that, you want to conduct your observations until you reach
what we call, "the point of least astonishment." This is the point
where, in each subsequent session, you're only seeing things you've
seen before.
Reaching this point means you have everything you need to build your
personas. Until you reach this point, you won't know for sure if
you've left something important out.
The good news is that it probably doesn't matter too much. While you
can make great strides with the initial design, improving efficiency
can't be done with only a single release. It has to be done
incrementally.
That means that you can get away with only interviewing a subset of
folks, probably chosen at random. Many of the important inefficiencies
and frustrating elements of the current process will emerge and it
should be easy to create personas, scenarios, and the innovations
you'll need to get major improvements.
Without knowing more about who these folks are, what they do, and how
the current system works, it would be hard to make specific
recommendations. However, you could start with a simple plan that
studies 15 end users (5%). Among the first things you'll want to do
with your studies is determine if there are others you need to study.
Hopefully, after seeing 5% of the population, you'll really have
enough sense of what your dealing with to know what else you need to
study.
Hope that 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
________________________________________________________________
Welcome to the Interaction Design Association (IxDA)!
To post to this list ....... [EMAIL PROTECTED]
Unsubscribe ................ http://www.ixda.org/unsubscribe
List Guidelines ............ http://www.ixda.org/guidelines
List Help .................. http://www.ixda.org/help
