There is not necessarily a link between the upstream site and this site.
These metrics have a greater level of accuracy, no matter what the ranking.
Certified Site Metrics are metrics that are directly-measured from the website instead of estimated.
The website owner has installed an Alexa Certify Code on the pages of their site and chosen to show the metrics publicly.
Daily Pageviews per Visitor Estimated daily unique pageviews per visitor on the site.
Daily Time on Site Estimated daily time on site (mm:ss) per visitor to the site.