Friday, August 7, 2015

NinjaTrader 7 Max Drawdown Percent Is Not What You Think It Is

Maximum Drawdown is a common metric used in evaluating trading systems. It is defined  as the largest equity peak to trough percentage loss.

NinjaTrader 7 includes a Strategy Analyzer for backtesting trading systems. The Max. Drawdown Percent value in the summary statistics is very different to the definition.

The Strategy Analyzer has no starting account size. Therefore by definition there can't a be maximum drawdown %. For example, if the largest drawdown in profits occurs immediately, the maximum drawdown % would be undefined due to dividing by zero.

Another consequence of no initial account size is that there is no equity curve. The closest thing is a graph of cumulative profit.

The maximum drawdown % value reported by the Strategy Analyzer appears to be the sum of percentage gains/losses for all the individual trades involved in the maximum cumulative profit drawdown. I can not think of any practical use for this number.

References. See the support articles here and here.

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