- Don't forget to read the class notes and accompanying papers on task-centered system design.
Good task examples:
- Says what the user wants to do but does not say how the user would do it
- you are not to make any assumptions about the system interface
- we will eventually use this to compare different interface design alternatives in a fair way
- Are very specific
- says exactly what the user wants to do
- we will eventually use this to specify the actual information the user would want to input to a system, and what information they will want out of it
- Describes a complete job
- should list all aspects of the task, from beginning to end
- this forces designer to consider how interface features will work together
- we will eventually use this to contrast how information input and output is carried through the dialog, i.e.:
- where does information come from?
- where does it go?
- what has to happen next?
- Says who the users are
- use particular people, if possible
- reflects real interests of real users
- the success of a design is strongly influenced by what users know and their real work context; we will eventually use this information to see if people realistically have the desire, knowledge and/or capabilities to accomplish their task with the system.
Example task description for a clerk in a video store, including discussion. The eventual system will assist the clerks to perform their tasks.
George Marlay, a regular video store customer, approaches Mary and asks if they have the Frankenstein comedy video. She asks if he means "Young Frankenstein" by Mel Brooks, and he say yes. She then directs him to the shelf where the video is expected to be. George retrieves the video card and brings it to the front desk. Mary asks for George's membership card, but George has forgotten it. Mary then looks up his membership number. Mary checks out the video, but reminds George that he has not yet returned the video "Brazil", which is now a day late. George says that he will bring it in later today, and leaves with the video.
Discussion. This task contains many typical clerk activities, which deals with vague requests about video titles, the location of the video in the store, forgotten membership cards, the video checkout activity, as well as reminders to customers about late videos. Most these tasks are frequently done, and important.
Mary Farness, an experienced full-time clerk at the video store, opens the store in the morning. She begins the day by checking in all the videos returned in the night video slot, which typically number between 90 to 150 videos <should have a list of these, including identifying text or other marks used to check these in>. She pauses her task whenever customers ask for her services. She usually checks in ten videos, and then re-shelves them before going onto the next ten.
Discussion. In this case, the "user" is the full time person who normally carries out this task. We expect them to be typical of an experienced clerk who will know the process well, and who will become well practiced at using the target system. The task is routine and frequently done.
Anil, a part time clerk who works the telephone, comes in for an hour every third evening. His job is to search the rental records to find customers who are at least one day late on their video returns. For example, he phones Bob Jakobs, who is two days late. Bob answers, and Anil identifies himself, tells him that he still has the video "Volcano", and reminds him to return the video. Bob says he will bring it back in an hour or so, and Anil crosses his name off the list. He then phones Ania Sliven, and says (more or less) the same thing. However, Ania says that she has already returned the video the day before. Anil puts her on hold, runs to check the shelf and finds the video there. He apologizes and hangs up. He then phones Ang Lee, but there is no answer. He makes a note that he should try this person again later. He continues in this manner. When he has finished the list, he starts again on those who have not answered.
Discussion. This task identifies a specific activity that is less frequently done but still quite important. It also indicates that a non-regular staff member may be doing this task.