Confused about how to translate something like “usability” into a number? The Nielsen/Norman Group has an article to help you do just that. It is meant as a comparison tool, but may be useful to give a baseline of an existing site in order to spot problems. The system is based on five components: task time, errors, memory, time to recall site structure, and subjective satisfaction.
Hit the link below to learn more about how to get a handle on measuring your website’s usability.
The Resource section is a curated section of this website containing information and articles I find useful to my process. You may find them useful as well.