The metric is designed to estimate the market sentiment

The buyer/seller prevalence is a metric based on the side of trades during the selected period. The metric belongs to $[-2, 2]$ interval. The more trades with ‘buy’ side available, the more positive the buyer/seller prevalence is.

The algorithm is as follows:

get all trades for the selected period

group trades by side (“buy” and “sell”)

calculate the sum of trade amounts in base currency

apply the following logic where $buy$ and $sell$ are the sum of buy and sell trade amounts

$prevalence = \left\{ \begin{array}{ll}
0 & \textrm{if $sell=buy$}\\
(buy-sell)/buy & \textrm{$buy>sell$ and $buy \leq 2 \cdot sell$}\\
2-buy/(buy-sell) & \textrm{$buy > 2 \cdot sell$}\\
-(sell-buy)/sell & \textrm{$sell>buy$ and $sell \leq 2 \cdot buy$}\\
-2+sell/(sell-buy) & \textrm{$sell > 2 \cdot buy$}\\
\end{array} \right.$

Here you can find the chart of how the applied function looks like.