Iterative testing
simply means testing that is repeated, or iterated, multiple
times. Iterative usability testing matters because the ultimate
goal of all usability work is to improve usability, not to catalog
problems. A single usability test - particularly if no action
is taken based on its findings - can only tell you how successful
or unsuccessful you were in creating ease of use. To improve upon
what you already have, recommendations based on the usability
test's findings must be incorporated into a revision of the product.
Once this has been done, it's advisable to test the product again
to make sure that no additional usability flaws were incorporated
with the fixes to the previously found glitches. In an ideal world,
of course, this cycle of testing would continue as long as meaningful
recommendations for improvement could be drawn from the usability
test results. In reality, it's best to define quantifiable goals
for your product's usability before you begin testing, and to
continue the cycle of testing and revising until your usability
goals have been met.
