Glossary » predictive metric
a value describing some aspect of a system that purports to provide a prediction or estimate of the usability of the system. For instance, if we described the font size used on a web page as a predictive metric (e.g. claiming that larger sizes are more legible, at least up to a point), then a designer would suppose that because increasing the font size improves their “score”, that doing so will also increase the usability of the design. This is in contrast to a descriptive metric, which makes no explicit claim as to the implications of the measurement.