Overall rating is the average of all user’s feedbacks, both as a buyer and a seller. It displays the overall users' performance, i.e. how responsibly they meet the requirements of the trade.
The rating serves as an indicator of the relative risk level. The higher the rating, the more likely it is that the risk of dealing with this particular trader is low.
This is why we ask our clients to leave fair and unbiased feedback after each trade. This will help the user pool to better identify trusted and experienced peers to trade with.
Also, don't forget to heed the rules of trade to build your own reputation.
It is calculated by averaging the ratings of each trade by summing them up and dividing by the total number of all trades.