Top Errors If we look at the top errors affecting the performance of healthcare domains, most of them appear to be simple on-page errors that can be addressed with rel- ative ease. For example, low text to HTML ratio, low word count, and pages with only one incoming inter- nal link — these errors are not too technical to be fixed but they are found on almost 100% of the domains we chose to analyze for our study. Other common on-page quirks include 4xx errors, bro- ken internal links, missing h1, missing meta descrip- tion, long title element, URLs with a permanent redi- rect, multiple h1 tags, temporary redirects, duplicate content, and broken external links. All of these missing or unoptimized elements appear to exist on more than 90% of the analyzed domains.