> In an upcoming project, the proposal is to use an agile iterative design method based on
> personas rather than functional buckets. personas would be developed out of a user
> understanding phase and the design interations would follow the persona scenarios.
> this is fine from a design development perspective but I am trying to work usability testing
> into this. my first draft was to do a comprehensive usability test of all (validated) tasks
> from the scenarios after the design phases on a mixed fidelity prototype. but there is
> some pressure to develop usability testing into the iterations.
> Does anyone have any suggestions as to how this can be done and why it would be better
> than a final usability test of the complete design?
I don't know if it's just a matter of language, but I think notions of
"design phase", "final test", and "complete design" are all antithetical
to the agile approach. Instead, I think in terms of iterative refinement
and continuous feedback. There is no complete design. Today, the design
is better than yesterday's thanks to what we've learned today. Tomorrow,
the design will be better still.
To me, usability testing is an important part of that learning. We have
many theories, and we try them out on real people to see how they work.
Then we refine our theories and try again. On my most usability-focused
agile project we did a few hours of usability testing every week, and
used that to shape both ongoing and future work. Once in production, we
also had an extensive set of metrics and A/B testing so we could get
statistics on user behavior. Again, we used that information every week
in deciding project direction.
So in sum, the reason the agile approach is better for usability is that
usability testing becomes an integral part of the design process rather
than the too-common case where it's a why-are-you-bothering-me afterthought.