Usability Testing

Basic Characteristics

Usability testing is a method to evaluate the usability of a product in an objective and comprehensible way.
Users or potential future user are asked to perform realistic tasks by using the product or a prototype of it.
Testing happens late in the development process. The product must be developped to an extent that performing a realistic task is possible
Fair testing is assumed. During the task performance there is no (or very limited) assistance by the researcher. One of the research questions is: "Can users perform and complete the task without assistance?"

Define test objectives
- Scope: Which part of the product is subject to evaluation?
- Criterion: What are the evaluation criteria you want to check for?
Define suitable task(s)
- based on realistic scenarios, formulated in the language of the users
- write instructions to explain the task to test persons
Test criteria - e.g.
- performance: e.g. speed, accuracy, number of errors, task completion
- workload, mental/physical/temporal load
- attention, situational awareness, mental information processing

define target users
- potential or real users
- based on personas
- subject matter experts
define sample size/number of participants
- small samples (3-4 part.) allow first hypotheses and problem detection
- larger samples allow high sensitivity and thorough detection of usability problems

e.g. sensors, footage, thinking aloud recording, eye-gaze-recording, surveys, etc.