"Target market segments must be able to make their first telephone call within five minutes of opening the product packaging in the evaluation prototyping home."

 evaluation prototyping article

"A network manager with at least two years experience, and with no measurable red-green visual deficiency, must be able to detect 99 percent of critical errors represented by color change from [rgb values to be defined] of a one-pixel-wide line connecting nodes on a visual display [specify makes], in lighting conditions representative of operations center X, over a one-hour period of typical peak hour traffic."

The Usability Trial A prototyping approach allows the usability metrics to be monitored constantly, from the moment that the relevant product feature has been included until the desired target has been reached. In a typical usability trial, which is usually recorded on video, users will be asked to carry out specified critical tasks. The session may conclude with a questionnaire or debriefing interview. Typical usability targets will refer to time of completion of a task, number of errors made, or quality of completed task. The usability trial, however, is also an opportunity to obtain users' subjective reactions to the prototype and to follow up on marketing issues where appropriate.

Usability trials often take place in laboratory conditions when the measures must be precise and the environmental conditions carefully controlled. However, field tests will more accurately reflect the end use situation. Implementation evaluation prototyping The heart of the user-centered usability engineering process is the cycle between prototyping and evaluation. However, sooner or later—ideally triggered by achieving the usability targets—the product is implemented and there is a greater investment in packaging, marketing, production, selling, and maintenance. Implementation can be seen as an evolution of the prototype-evaluation cycle, moving out of the development laboratory and into the marketplace. Every product can be seen as a set of hypotheses with the ultimate test of success being profitability by evaluation prototyping.