Perform a cognitive walkthrough for the following situation:

System: The telephone answering machine or messaging system you have at home or at work.

Users: First-time users of the system, without training and without a manual. (If the system isn't on a separate machine, assume the user has the minimal documentation -- maybe a template on the touch-tone pad, or a wallet card summarizing key commands.)

Task: Check for messages, find there are some (five), play them, replay the second one, and then delete all of them. Note that "delete all five messages" may have different meanings depending on the system you are using. For some systems, it may mean positioning the cassette tape so the next messages will overwrite the old ones.

Other systems might not require any action -- maybe new messages automatically overwrite old ones, or maybe old ones aren't saved unless a special command is issued. In any case, assume your user wants to "delete" the messages because that's what he or she has always done with other answering machines.

What to write up: A BRIEF description of the system -- a sketch of an answering machine would supply most of the details, and you can include more information later in the walkthrough stories. The list of correct actions. A story for each action. It can be short, but it should touch on all four important points: o is the user trying to do the right thing? o is the correct action obviously available? o will the user connect the correct action to what they are trying to do? o after the correct action is performed, will feedback show it was the right thing to do? If there were problems, suggest how they could be fixed. A note on strategy: Like the designer of a system, you are probably intimately familiar with this task on your own phone answering system. Try to use the walkthrough procedure to distance yourself from that familiarity.