Metric: aXe Accessibility
It can be useful to run a live check on your page while fixing errors. Instead of running a new page scan, you can simply use the SiteMaster aXe bookmarklet to audit the page. Results of the audit will be displayed in your developer tools console, where you can select an error to inspect the related element on the page. The developer tools are also instrumental in identifying and fixing the accessibility problem (for example you can see where CSS styles came from and edit them on the fly).