Not all relevant aspects of a product can be tested under lab conditions. It must be evaluated in the intended application context and with routine tasks. If the evaluation context is too constrained, critical problems may remain invisible.
How can we test our system in the field? How can we evaluate our system with diverse groups and under various external conditions? (reflection aspect: values)
Ostendorp et al. (2013) studied stressful situations of computer use where lengthy subtasks running in parallel cause waiting periods for the user and interfere with their concentration on a main task. The aim of the project was to reduce the associated stress for the user. They developed an “ambient progress bar”, a row of RGB-LEDs attached to the back of the monitor. It showed the progress of some parallel running process by colour gradient for peripheral perception. In fact, the device had a stress reducing effect. However, the “ambient progress bar” was only tested under laboratory conditions. In a more realistic environment, e.g., an open plan office, it might have been tested whether the lights have disturbing effects on co-workers.