Quantifying the User Experience

A statistics book aimed squarely at people who run user research, organised around the questions that actually come up in the work. It covers confidence intervals for completion rates and task times, comparing two designs, sample size calculations for both usability studies and surveys, and standardised questionnaires such as the System Usability Scale. Each chapter opens with the practical question and then shows the working, with formulas and small datasets you can follow along with. The second edition adds material on regression and on the measures used in loyalty and satisfaction research. Read it when your findings need to survive contact with an analytics team.