Inconsistent Backtesting Results

[BQuinton]

Hello,

I was backtesting a strategy and getting inconsistent results. The only thing I changed between the tests was the timeframe I was testing over.

If I just tested over the last 22 days (1/2/23 to 1/25/23) it would show 8 trades. However, if I increased the time window to cover the last four months there was only 3 trades. And when I increased it to test over all of 2022 there was 0 trades executed.

I used the same code, the same settings, etc. Just changed the timeframe.

I haven't seen this with other strategies and am at a loss at what could cause this, so I'm not sure how to troubleshoot it. Any advice of where to start is appreciated.

[NinjaTrader_BrandonH]

Hello BQuinton,

Thanks for your post.

As a general rule for backtesting: Same Input data + Same strategy code and parameters + Same timeframe = Same results.

I've included some additional resources on the differences between historical and realtime data and further reading on these discrepancies that should be minded while backtesting. My colleague Chelsea's forum post goes into depth on creating strategies and backtests that produce consistent results.

Discrepancies between backtesting and realtime data — https://ninjatrader.com/support/help...ime_vs_bac.htm

Comparing real-time, historical, and replay performance — https://ninjatrader.com/support/foru...d.php?t=102504

Also, re-download the historical data you are testing on to ensure you have historical data for the timeframe you are backtesting by going to Control Center > Tools > Historical Data > Download.

Download historical data: https://ninjatrader.com/support/help...8/download.htm

To fully understand how a strategy is behaving and placing orders, debugging prints should be added to the script to see exactly how the logic is processing.

Below is a link to a forum post that demonstrates how to use prints to understand behavior.

https://ninjatrader.com/support/foru...121#post791121

Please let me know if I may be of further assistance.