Metric analysisWhile conducting product usability tests, designers must determine and then usea set of metrics to identify what it is they are going to measure. These metrics areoften variable, and change in conjunction with the scope and goals of the designproject. Qualitative design issues such as user satisfaction are often testedalongside more functional usability tasks. These metrics are then measured,producing data such as the percentage of users that completed a task, how longit took the sample group to complete the tasks, the ratio of success to failure tocomplete them, and the number of times users appeared frustrated. The ultimategoal of analyzing these metrics is to find/create a prototype design that users useand like- to successfully perform given tasks and interactions.Rapid iterative testingRapid iterative testing and evaluation (RITE) is a form of product usability testingthat encourages testers to 'think aloud', enabling the design team observingparticipants to step in and change the user interface of a product, interface orservice once a problem has been identified and a rapid solution been devised.The RITE technique is arguably less methodologically robust than traditionaltesting, but it does dramatically reduce development time, and is commonly usedin the software development field