Quantitative data collection is the part of usability testing where you turn what happens in a session into numbers you can compare, report, and defend. The core metrics are familiar ones: whether a participant completed the task, how long it took, how many errors they made, and how difficult they said it felt. On top of these behavioral measures sit standardized attitudinal instruments such as the System Usability Scale (SUS) and the Single Ease Question (SEQ), which have been used widely enough that your scores can be compared against established benchmarks.
What makes these numbers trustworthy is not the arithmetic but the discipline behind it. You need a data collection instrument prepared in advance (a scoring sheet or form with explicit definitions of success, error, and start/stop points for timing), consistent administration across every participant, and a clear plan for how individual scores will be aggregated into summary values. Without that consistency, two observers watching the same session can record different results, and the resulting averages are meaningless.
The three videos below come from Nielsen Norman Group and cover the standardized questionnaires most often used in practice, how to choose between them, and the important caution about collecting metrics in small qualitative studies. While watching, pay attention to exactly when each instrument is administered, how scores are calculated and interpreted, and what sample size a metric realistically requires before you should treat it as a number rather than as a story about one user.
An introduction to the System Usability Scale, a ten-item survey given to participants at the end of a test session to capture perceived usability. The video is likely to explain the question format, how responses are converted into a single score, and how that score is interpreted against known benchmarks.
SUS is the single most widely used standardized usability questionnaire, so this directly supports the Standardized Usability Questionnaires subtopic, and NN/g is a recognized authority whose guidance on scoring and interpretation is reliable.
A short comparison of two standardized instruments: the System Usability Scale, administered once at the end of a session for overall benchmarking, and the Single Ease Question, asked immediately after each individual task. It discusses how each fits alongside qualitative methods and what kind of question each is suited to answer.
Choosing the right instrument and administering it at the right moment is central to designing data collection instruments and keeping measurement consistent across participants, which this video addresses directly.
This video addresses the common situation of wanting numbers from a small qualitative study. It explains that metrics from individual users can help illustrate how each person performed, while cautioning against treating averages from a handful of participants as statistically meaningful findings.
It gives students a realistic view of aggregating quantitative data and the limits of small-sample metrics, which is essential for distinguishing defensible numbers from misleading ones in the kinds of studies run in this course.
Together these videos give you the measurement side of a controlled test session. They supply concrete, standardized instruments (SUS and SEQ) and the timing rules for administering them, which supports facilitating sessions with consistent protocols (MO1) and collecting quantitative usability data alongside observational and think-aloud notes (MO2). The discussion of metrics in small qualitative studies also builds the judgment needed to recognize when numbers are valid versus when sample size or inconsistent administration has confounded them (MO3). Use them as a basis for the scoring sheet and post-task or post-test questionnaire you will prepare before running your own sessions.
These videos were chosen from YouTube on October 3, 2026. Each has captions; the player turns them on. Videos on YouTube can be changed or removed — if one no longer plays, tell your instructor. If a player does not appear, use its Watch on YouTube link.