In this article I will go through:

1. What Behavioral Metrics are used to measure UX performance
2. Which situations they are best used in
3. How to improve the reporting of each metric
   
   

1. Task Success Rate

What is Task Success Rate?

• The simplest usability metric that gauges whether participants can complete a single task.
• This metric is both easy to understand and represents usability’s bottom line.
• Task Success rate is a % measured by dividing number of successful tasks by total number of tasks x 100 (see diagram below)
• It is a quick gauge of whether users are able to successfully complete a task.
• If the rate is low then then there is room for improvement in the user experience.
• 1 = success, 0 = failure

When to use Task Success Rate

• Tasks like completing a signup process or adding a specific item to a shopping cart are well-suited for this metric.

How to improve reporting Task Success Rate

• Make sure tasks are clearly defined.
• Keep in mind, success rate doesn’t explain how well users perform tasks or why they fail them.

2. Time-on-Task

What is Time-on-Task?

• Usually communicated as the final UX KPI.
• The time-on-task metric can help managers track design progress and support decisions about when to release a product.
• Average time-on-task is measured by adding up all users’ times and dividing by number of users (see diagram below).
• The rule of thumb is…"the shorter the processing time, the better the user experience."

When to use Time-on-Task

• Use time on task when you want to validate whether your new design improves experience of users by cutting out inefficiencies.

How to improve reporting Time-on-Task?

• You can improve your reporting of this metric by using the geometric mean for small samples (fewer than 25) and the median for larger samples.
• Time-on-task is a quantitative measure. There are many ways to achieve good time-on-task - not all are good. To improve the reading of this metric it is recommended to include a qualitative metric to your mix which I explain in our next article on Attitudinal Metrics.
• It’s also important to track this and other Behavioural Metrics over time for more accuracy.
• Don’t get hung-up on "what the right task time is" because it’s practically impossible to achieve. It’s the relative comparison to new designs or competitors that provides the most meaning.

3. Task Ease

What is Task Ease?

• Task Ease is determined using The Single Ease Questionnaire (SEQ).
• The SEQ is a post-task, single-question, questionnaire given upon the completion of each task in a test session. It gauges the difficulty of tasks by asking users to rate how hard the task was on a 7-point rating scale.

When to use Task Ease

• It’s administered immediately after a user attempts a task in a usability test. Use when you are specifically interested in the usability of the individual components.

How to improve reporting Task Ease?

• The correlation is not so strong that any single usability metric is a replacement for another, but it does tell us that the metrics are measuring overlapping things.
• Improve your reporting of this metric by endeavouring to see how users do when attempting the same task on a comparable website to really gauge how difficult the task is relative to its inherent complexity.

Conclusion

Behavioral metrics are good to use when you want to quickly determine whether or not a task is working to standard. They are good to use when first developing a product as you will be able to spot and improve tasks quickly. However, as quantitative measures, they don't tell you "why" users aren't able to perform tasks. To have a more holistic overview of the performance of your product and to improve Performance Monitoring in general, you should use a mix of Behavioral and Attitudinal Metrics - which I will go over in my next article.