[Sigia-l] comparing personas, scenarios, uses cases, task ana lysis

[George Olsen]

It's helpful to think of various kinds of documentation as an interative
process in itself.

Scenarios provide early "rough descriptions" of how things will work in
more human-friendly format -- and they're useful for presenting
functionality to senior management. They're also more front-end oriented
-- they're about what the user sees (and users don't care about what's
going on backstage.)

As things evolve you need to fill into the specifics, especially all the
details needed to make the back-end run.

Use cases (and supporting information) provide that sort of fine-grain
detail -- and tend to be more machine-oriented.

My experience is that once the initial scenarios are developed, the
refinement of both scenarios and use cases can proceed in parallel to some
extent. Obviously they need to be kept in synch, but the systems analysts
can focus their use case efforts on the parts of the scenario that are
stable, and even if the scenario isn't completely nailed down they can
start coming up with rough ideas about what they'll need.

Scenarios, high-level flow maps, personas, etc. also tend to complement
traditional IT deliverables nicely, since they provide a sense of the
forest rather than just the trees -- which can help the programming team
visualize the final result.

For example, on one recent project I created screen mock-ups that were
annotated with brief descriptions of the functionality of each screen
component. That was stapled to a use case flowchart by the systems analyst
that spelled out all the functionality, including back-end stuff like
error catching, etc. Then we stapled on the specific details, such as
field descriptions, permissions, content on the page that needed to be
pulled from the database, etc.

The programmers liked this because they could see how the parts related to
the intended whole, which doesn't necessarily happen with traditional IT
documentation.