This quality characteristic is tested by seting up a controlled environment, inviting typical users to complete a set of tasks with the product and measuring their levels of satisfaction/success or error rate/frustration. 1. Usability 2. Functionality This quality characteristic is tested by setting up monitors that measure throughput in areas such as the number of completed HTTP requests or database operations per second. 3. Efficiency This quality characteristic is tested by performing an operation for which you know the correct outcome and compare the actual result with the result that was expected