Expanding the formula X - index of the quality of the site Yandex

Justifying the name of a new indicator, Yandex does not disclose the formulas for its calculation, limiting itself only to general phrases that, in determining the quality index, all information available from Yandex is used, obtained from its various services.
What do we have to do? That's right, conduct research and get to the bottom of the truth!
The study was based on data from 705 largest forums of Runet, Uanet and Bynet. Information about the forums was obtained from the forum forums rating .
X and TCI
To begin with, the most logical would be to compare the performance of the X with its predecessor TCI.

As can be seen from the graph, no relationship between these indicators is observed. So, Yandex was right: the era of SEO links is over, you need to focus on other indicators. But which ones?
IKS and Alexa
Alexa.com with the help of the toolbar determines the most visited Internet sites and builds them into a rating. Thus, Alexa ranking is the position of the site in terms of traffic throughout the Internet. The lower the number, the more popular the site.

And here we see a correlation between IKS and Alexa! Thus, we can conclude that the rating of the X depends on the attendance of the site.
To check the guess, let's turn to statistics LiveInternet.ru ...
X and LiveInternet
One of the LiveInternet.ru services is the attendance counter. Of the 705 forums participating in the study, 311 (44%) have an installed and working counter LiveInternet.ru.

The above diagram confirms our guesses: X is directly dependent on site traffic.