Project 5: Formative Usability Evaluation

Due as per class calendar.

Overview

This step in your usability engineering process is the real payoff. It's where you find how good the usability is and where you identify the usability problems. Most students think this is the most fun and most rewarding part of the project. The essence of this assignment is to carry out a full set of formative usability evaluations on your computer-based prototype, following the detailed techniques described in the class notes and discussed and practiced in class. 

What To Do

Before Data Collection Session
  1. Pilot test your high-fidelity prototype some more.
  2. Select user participants.
  3. Decide team roles. Prepare blank data collection forms and Quis-style user questionnaire.

During Data Collection Session

  1. Get ready and have participants from the appropriate user classes perform benchmark tasks using your prototype.
  2. Take quantitative and qualitative usability data. Then finish up with each participant.

After Data Collection Session

  1. Do usability data analysis.
  2. Compile a list of usability problems identified in your testing.
  3. Do cost-importance analysis to decide which problems to fix.
  4. Consider what you learned in this formative evaluation process.

How To Do It

  1. The first things to do before you start any usability testing are to pilot test, pilot test, and pilot test. Get at least one person outside your team (it's OK to use people from other teams, but just for the pilot test) to go through your testing routine as a participant. The primary goal for pilot testing is to make sure the prototype is complete and bug-free and that it will support usability evaluation without breaking. Also, from just this quick and simple pre-evaluation activity, you will learn a lot and it will help you tune and calibrate your formative evaluation setup. As a result you may make changes to your usability specifications, bench mark tasks, testing procedures, etc. Make sure to do enough pilot testing to shakedown the benchmark tasks and usability specifications you have chosen for evaluation. Don't yet fix usability problems found in pilot testing.
  2. Select user participants. Enlist at least 4 representative users from your client organization. Your user participants should cover all of your defined user classes. Use more participants as necessary for your own situation. The rule of thumb is 3 to 5 users. This number is 'per user class', because each user class requires potentially a new test, with different benchmark tasks and different usability specifications. For this class you can use as few as 2 participants per user class and not get penalized. Sometimes, when even 2 participants are not available for a user class, you should use what you can get. You should explain and justify this kind of exception.
  3. Decide team roles. One person should be the evaluation leader or facilitator, to meet and greet the participants, to keep the evaluation sessions moving, and to interact with participants. Another person should be responsible for taking quantitative data (e.g. time on task and error counts). Everyone else should record (write down) qualitative data (e.g. critical incidents and comments by the participants).

    Gather up the 5 or more benchmark tasks you created in Project 4 and print each one on a separate sheet of paper. At this point you should also prepare several blank data collection forms. You'll need at least one form per benchmark task per user participant
  4. Before each participant arrives, get your prototype "booted" up and ready to go. Then greet the participant. You will meet each participant at a predetermined time and place, often at the client site. Explain the procedure; give the participant any general written instructions about the overall process. Show them any setup you have and answer any questions they might have. If you are using an informed consent form, have them sign it now.

    Give the participant the written benchmark task description for the first task, appearing alone on a single sheet of paper. Let them read it, and answer any questions. (Reading time is not part of task performance time.) If your plan to collect verbal protocol data, ask the user to "think aloud" while performing the task. Tell them when to start, so you can start timing, etc. Do not instruct or coach the participant in details of how to perform a task as they are working. If they get completely stuck and frustrated, then give them a hint, but avoid telling them specifics. The idea is not to get them through the tasks but to discover usability problems in your interaction design. Repeat the same for all the benchmark tasks. You are expected to run all the benchmark tasks you developed in (Project 4) with real participants.
  5. During the usability evaluation session the team member selected for the role should take quantitative data (e.g. time on task, error counts). Others should take extensive notes on critical incidents and verbal protocol data; the Data Collection Form is a good place to put these notes. Also, after performance measurement is completed (so you don't interfere with measurement), talk with the participant about the task, etc., as you saw in the video in class. Also have the participant do some "free play" and generally interact with the design and take some verbal protocol. This can catch some problems not seen in your benchmark tasks, which are by nature more limited in scope. At the end of each session, have the participant fill out the questionnaire (that you created in Project 4) for your selected questions. Then thank the participant, answer any final questions they may have, and give them their "reward".
  6. After testing is over, do a complete work-up and analysis of both the quantitative and the qualitative data, following the techniques described in the class notes and in-class activities. Compute the average values for your quantitative measures and compare them with your usability specifications, as described in the deliverables below. It is normal for a design to not meet your usability specifications in the first round of usability testing. That is why it is an iterative process. If you meet most or all your usability specifications, we will be suspicious that the design was too simple, the benchmark tasks were too easy, or you set the target levels too leniently.
  7. From your notes, the critical incident data, and the verbal protocol taking, compile a complete list of usability problems discovered across all your usability evaluation sessions. You should easily find a dozen critical incidents (indicating usability problems) in your usability evaluation; more is not unusual. If you don't, I would be suspicious of something -- your design is not rich enough, your benchmark tasks are too easy, or there is something wrong with how you did the process (e.g., not seeing all the critical incidents). In such a case, reconsider and revise something and do more formative evaluation until you have enough critical incidents.
  8. Do a complete cost-importance analysis, as we did in class. Use a cost-importance table to show, for each usability problem, your estimated importance to fix and cost to fix and your priority ratios and rankings. Combine related usability problems, as we did in class, representing the combination as a single new problem in the table. Show the original separate problems and the group problem together, as we did in the "Grouping Example" in the class notes. Do the cost-importance analysis (ranking, etc.) based on the grouped problems, not the original individual problems that comprise a group. Pull out Must Fix problems, if any, and put at the top. Sort the rest by descending values of priority ratio. Assign yourself a fictitious number of person-hours as the available resources to fix problems and draw a line in the cost-importance table representing where you will run out of resources (i.e., the line between "can fix" and "put off"). Show your final resolution for each problem (e.g., must do, will do, do if time, next version, probably never, etc.).
  9. As a team, discuss process problems, lessons learned, and what you got out of this process. Take notes for reporting in the deliverables.

Deliverables

Inside the binder, create a "tabbed" section labeled "Project 5". Add this section to the front of your team binder. This way, your binder becomes a cumulative record of your whole project, with the most recent parts first. This section should start with its own separate cover page with (mostly the same as on the front of the binder):

Contents of Project 5 section.

Number and label your items per this list:

 

8. In a cost-importance table list each usability problem discovered. The problem list should contain at least a dozen usability problems and should be sorted by ascending values of priority rank, with any Must Fix problems at the top. If you found a great deal more than that, list the dozen or so most significant (or most interesting) ones, showing this summary information:

 

Discuss any groupings you made, combining individual related usability problems into one broader problem. List only the final merged problem in the table. Indicate the number of person-hours you have allowed yourself as a hypothetical limit and show it on the cost-importance table as a "cutoff" line. Then show your final resolution (to fix or not) of each problem, based on where each usability problem falls in the rankings with respect to that limit.

9. Conclude the report with a brief statement reflecting on how the process worked (or didn't) for your team, any important lessons learned, the kinds of problems encountered by you and/or the participants, what the participants liked and disliked, and reflections on the prototyping and formative evaluation processes.