The performance method used is TWR which stands for Time Weighted Return.
A TWR measures the performance of a dollar invested in the system since inception.
Its distinguishing characteristic is that cash inflows, cash outflows and amounts invested over different time periods have no impact on the return.
TWR is the best method when benchmarking your portfolio against another as it measures your investing decisions unlike a money weighted return, which measures how good you’ve timed your deposits/withdrawals.