Frequently asked questions

The WatchMouse Site Performance Index (SPI) quantifies the users' perceptions of speed and availability of a site into a single number.

The SPI is computed by adding up the time needed to load the main page and adding a penalty for each failed request. The higher the number, the lower the customer experience of the site e.g. sites with an SPI of 1000 or less perform well, whereas an index of 2000 or more, is an indication of a site with serious user experience problems.

• How come WatchMouse measures the quality of hosting providers by measuring their homepages, rather than those of their customers
• How is the Watchmouse Site Performance Index computed?
• Isn't your research methodology a bit too strict?
• The SPI seems unfair as pages with a lot of text will take more time to load than simple pages.
• What is the Watchmouse Site Performance Index?
• Why does the SPI only take a limited amount of content into account?