The index is characterized by being entrepreneurial by nature, where are represented the most representative national websites of the various sectors of activity or of the financial sector  particularly in the case of Financial Index. The websites in the index show a necessary balance by sector of activity, being the main criteria for inclusion, the visibility of the website, the permanence in other tops of reference, and, ultimately, its good performance when compared to other websites in the same sector . The index will be reviewed on a quarterly basis to reflect the rapid changes on the Internet.

The Index is calculated based on hourly measurements of the performance of each one of the websites, from 8 am to 8 pm, from Monday to Friday. In every hour, five Keynote measuring officers access to each one of the websites, measuring the length of time to download the main page of the website, and all objects referenced therein. 

In the event of an error, that value is not considered for purposes of performance Index, but it is considered on the availability. An error can occur when you can not access the website, or even when you can not download one of the objects referenced. If there is an excessive number of errors during the measurement week, the website will not enter in the Index table's.