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Dear Ms Castellanos,

Terri McNichol sent me a copy of your note regarding doing
formative evaluations of interactive exhibits.  As someone who
did the first formative study back in the mid-60s, and have
done dozens since then, I can give you some guidance on the
selection of samples.  First, define your target audience in
terms of age and education. If the exhibit is for the kind of
audience you normally get (or expect), then pick from that
audience.  If the exhibit is supposed to "work" for children
down to a certain age, then make sure you have at least 10
from that age group, mixed boys and girls. Adults can be
randomly sampled from both genders, with 10 women and 10 men.
Look at  your results at that point and see how consistent
they are and how clearly they point to problems with the
exhibit.  If they do (which they almost always do) try to fix
these problems before you do more studies.  Then repeat the
above sample, and see if the "fix" works.&nbs! p; If it does,
you are through.  If it does not, try again.  The important
thing is not numbers, but careful examination of the behavior
of people as they use the exhibit.  I have made changes in an
exhibit based on three people using it because it was so
obvious what was wrong that it would be stupid to continue the
study until some changes were made!!  Common sense is the best
guide to doing formative evaluations!

I know you have trouble getting publications, but I must
recommend an article in the latest issue of the Curator,
called Designing With Multiple Interactives: Five Common
Pitfalls, by Sue Allen who is at the Exploriatorium in San
Francisco.  If you can't get this issue, drop Sue a note at
[log in to unmask]  I am sure she will share this with you.

Hope I have been helpful.

Harris Shettel
Museum Evaluation Consultant
Rockville MD 20853
USA

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