The effect of time period of backtest in the result

[sa.ba]

HI every one
my robot in 2 different period of time of back test represents 2 various results?
In some cases it calls to 0 and in some its profitable?
which one i can trust?
I have used trading stop for take profit in the strategy an I saw that the last opened trade remain open for a long time and closed by a big loss or closed in one day by a big loss
Im so confused, may you help me please?

[sktsec]

Backtest is not reliable

[l'andorrà]

Backtest is just useful to discard terribly bad or simply bad strategies but never to find specifically profitable ones. The best you can do is making backtest the less unreliable possible, but it will always be unrealiable to a degree. Forward testing is definitely more reliable.

[sa.ba]

@l-andorrà
Thanks a lot for replaying my questrion

[samuelkken]

@l-andorrà what is forward testing?

[l'andorrà]

@samuelkken Trying your strategy on a demo account for a long time.