Quality software—that is what we are seeking. While this is clearly a goal of any software tester or quality engineer, what exactly is the definition of quality software? Part of the answer is easy. There are many aspects of software that we can test and measure and to which we can assign a number. Some examples are how often the software crashes, how long it takes to complete a given task, or how much memory is being used. We can also look at how many of our tests pass and how many fail. While these quantifiable measures are important, they do not provide a complete picture of software quality. There are other more qualitative aspects of the software that also need to be considered.