Backtesting is Different
There are several explanations for the problem - the most likely one being the spread widened. That often happens when the market is volative.
I don't know how many trades you took but if the spread went from 5 to 15 pips, that can be signifigant after a few trades. On backtesting, the spread is constant - the same as current spread, not the spread at the time of the trade.
Are you backtesting in every tick mode? That will make a huge difference.
Hi,
Thanks ... That about spread I didn't know!? But I use always Every Tick so I don't think that is a case ... or not?
If backtesting is different - why is backtesting used for if it is different from like system?
Depends
Backtesting can be very useful when you understand it and use it properly. As a programmer I use it to verify the correctness of my code and to test specific scenarios. In forward testing that would take weeks or months. With Strategy Tester it only takes a couple of hours or a day if it is really tricky.
As a trader using someone else's code, I can learn a lot about how it performs in a general sense. I am always aware of its shortcomings and thus my expectations are realistic.
OK ... but I tried Optimization on eurusd and I setup some ranges for input parameters and after hours and hours of executing I got few combinations which 'works'.
After that I setup manually one of those 'winning' combinations and run backtesting on same pair and same period and I got totally different results ... I tried another combination - it end up on balance 0.
What I am doing wrong? What is correct, optimization or backtesting results? Same MT4, same data, same period, same same same everything?
Never Tried It
I have never used optimization but I am sure others have - just do a search.
Backtesting on ECN brokers are not working.
B.
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Hi,
I left my EA working on one demo account on GBPUSD ... and this morning GBPUSD crashed so all my demo amount was wasted. I came home and I am trying to re-produce same scenario in backtesting to try to improve EA but I am getting different results whatever I try. It also loose a lot of money but not as during forward testing. What is wrong here and how come performances of EA on forward testing and back testing are different 100%. Same data, same MT4, same account, ... same everything![](https://c.mql5.com/forextsd/smiles/rolleyes2.png)