Task Performance Indicator (TPI) methodology
What's a Task Performance Indicator and what makes it stand out from other usability tests?
Remote usability testing
Participants don't come to a lab but carry out the test from home or place of work. The participant can use his or her own device and is in a trusted environment.
Focus on top tasks
Tasks that will be tested are based on the customer's top Tasks. This involves a substantial methodology for developing task questions, which are significantly different from tasks themselves. It's crucial to create tasks that are measurable, clear & precise and can be repeated time-over-time.
Participants will be representative; they will reflect the target audience of the website, app or intranet. It's crucial in ensuring we get accurate, defensible and reliable results.
Recording of audio & screen
Using screen sharing technology, the facilitator is able to see the screen and hear the voice of the participant. Video & audio will be recorded for analysis afterwards.
and of course:
It's an on-going management model
The Task Performance Indicator is an ongoing management model. You can track the performance of customers tasks over time, making improvements and then seeing how the score changes. If you make improvements to your website or app, then these improvements will show up as higher success rates and lower task times the next time you run a TPI. That's makes the Task Performance Indicator a perfect management KPI for customer experience.
What does the process look like?
It's a well-defined process that allows you to measure the performance of tasks on your website, app or intranet over time. The stages are:
- Identify tasks you want to measure
- Recruit participants
- Carry out the usability study
- Process results and recommend improvements
- Repeat every six to twelve months
(Unless you haven't changed anything)
How are TPI scores defined?
Participants will be asked to perform a task. Once they understand what they have to do, they will indicate they're going to start the task. At the end of the task, they must provide an answer for the given task. This allows us to calculate a score based on:
Completion Rate (%)
The completion rate is the percentage of participants completing a specific task. It is calculated by taking the number of participants who have successfully completed the task, divided by the total number of participants who have carried out the task.
Average Completion Time
We can also calculate the completion time for a specific Task. This is calculated by taking the average completion time based on the completion time for participants who have successfully carried out the task.
Participants are not judged based on whether the provided answer is correct. And the participants are allowed to provide feedback and even give up when they are not able to complete the task.