User Experience Design Quality Control & Assurance 3 — Questions and Answers
Question 1: Which metric BEST captures how efficiently users can complete a task during usability testing?
- Net Promoter Score (NPS)
- Task time on completion (time-on-task) (Correct answer)
- Bounce rate
- Daily active users (DAU)
Correct answer: Task time on completion (time-on-task)
Time-on-task directly measures efficiency by recording how long successful users take to complete a defined task.
Question 2: A UX auditor identifies that the same action is labeled 'Delete' in one area and 'Remove' in another. Which quality issue does this represent?
- Poor visibility of system status
- Inconsistent terminology violating consistency and standards (Correct answer)
- Lack of error prevention
- Insufficient contrast ratio
Correct answer: Inconsistent terminology violating consistency and standards
Using different labels for the same action violates the consistency and standards heuristic, forcing users to wonder if the two terms mean the same thing.
Question 3: In a UX quality framework, what does 'error rate' measure?
- The number of server-side 500 errors per session
- The proportion of user actions that result in mistakes or incorrect steps during task completion (Correct answer)
- The percentage of users who abandon the app after seeing an error message
- The frequency of failed API calls within the product
Correct answer: The proportion of user actions that result in mistakes or incorrect steps during task completion
Error rate in UX testing measures how often users make incorrect actions (wrong clicks, form mistakes) while trying to complete a task.
Question 4: What is the recommended minimum number of participants for a moderated usability test aimed at finding the most critical usability problems?
- 1–2
- 5 (Correct answer)
- 20
- 50
Correct answer: 5
Nielsen's research shows that 5 participants uncover approximately 85% of usability problems, making it the widely accepted minimum for cost-effective qualitative testing.
Question 5: A QA checklist item states: 'Every form field must have a visible label that is not removed on focus.' Which standard does this rule primarily support?
- ISO 9241 ergonomics standard
- WCAG Success Criterion 1.3.1 (Info and Relationships) and 3.3.2 (Labels or Instructions) (Correct answer)
- Material Design component guidelines
- GDPR data minimization principle
Correct answer: WCAG Success Criterion 1.3.1 (Info and Relationships) and 3.3.2 (Labels or Instructions)
WCAG 1.3.1 and 3.3.2 require that form inputs have programmatic labels and clear instructions so assistive technologies and users can understand what is required.
Question 6: During cross-browser QA testing, a designer notices the layout breaks on Safari but is fine on Chrome. What is the MOST likely root cause to investigate first?
- Server response time differences between browsers
- CSS properties or JavaScript APIs that lack full support in Safari's WebKit engine (Correct answer)
- Differences in screen resolution defaults
- The CDN caching policy for static assets
Correct answer: CSS properties or JavaScript APIs that lack full support in Safari's WebKit engine
Safari uses the WebKit rendering engine, which historically has lagged in supporting certain CSS features and JavaScript APIs that other browsers support.
Question 7: Which of the following BEST describes the purpose of a UX benchmark study?
- To explore open-ended user needs before any design exists
- To establish baseline performance metrics so future design changes can be compared against them (Correct answer)
- To test whether a prototype satisfies accessibility requirements
- To gather demographic data about the target audience
Correct answer: To establish baseline performance metrics so future design changes can be compared against them
Benchmark studies measure task success, time, and satisfaction at a specific point in time, creating a baseline for evaluating the impact of future design changes.
User Experience Design Quality Control & Assurance 3
Which metric BEST captures how efficiently users can complete a task during usability testing?