Quote from walterjennings:
not true for all cases. i found one difference between sim and live which effected me was when my system attempted to grab liquidity which faster systems got to first. obviously that had a negative effect on the system and has nothing to do with curve fitting.
IB gives you a sim fill for a market order at the next 'last price' after you transmit (not realistic), with limit orders IB gives you a fill only if someone else trades at your limit price (also not realistic).
If you're talking about high frequency trading (and some scalping), then sure... liquidity, latency and computer will greatly affect the performance.
If minor data issue was a problem, he should be setting up his trading environment differently. More-so, he "really really really" needs to step-up his testing skills and equipment going into every detail from acquiring access to institutional level quotes to execution...
Frosty is using a time bar chart making only 3 trades a day. He's trading style is supposedly trend-following (intraday swing?). The problem doesn't lie in the quote and execution platform. If this were true...
He's hypothetically made around 60 trades... if it's a point slippage for each... he's still deep down... or is he getting +5 tick slippage for each trade????
Considering the system to be working... let's all be serious... he's not losing because of unnecessary slippage....