As our data and these examples show, you don’t always need fancy metrics or statistics to provide quantitative support for UX decisions. You can do a lot with simple binary data and this powerful formula. Keep in mind that the formula is part of a larger strategy for interpreting the data and using it to guide decision-making. You can never be sure about the accuracy of a simple proportion or percentage, but you can have a precise amount of confidence in the adjusted Wald confidence interval computed from the same data. In this way, the Adjusted-Wald Interval supports confident decision making in UX design.