The article discusses the importance of measuring user experience (UX) objectively through metrics, rather than relying solely on subjective opinions. It argues that measuring UX allows designers to evaluate their work more rigorously and avoid biases influencing decisions. 

Several commonly used UX metrics are described in detail. Task-based metrics like Time on Task and Levels of Success directly assess how easily users can complete tasks. Study-based metrics like UMUX-Lite and NPS evaluate overall user satisfaction and perception after interacting with a product. 

The article provides guidance on choosing appropriate metrics based on project goals and constraints. It also explains how to calculate scores for some metrics and interpret the results, with an example of measuring checkout success on an e-commerce site. 

Basic statistical concepts are introduced so designers understand how to determine confidence intervals and margins of error when analyzing metric data. This helps communicate the reliability of findings.

In summary, the article advocates for applying objective UX metrics in design work to replace subjective judgments. It offers actionable advice on selecting, implementing and reporting on metrics to evaluate the user experience of digital products and iterations.