Quote from tickzoom:
This is so *almost* true. I mean that for the longest time I quit back testing and just did market replay, would see a new condition and add a rule.
But the biggest problem with back testing was that the data doesn't close enough simulate a real live trading situation.
For example, I work in USD/JPY and the most realistic data I can get for 5 years has only non-duplicate ticks, and only the bid prices.
Only bid prices. I started collected my own data with bid/ask and 5 levels of the DOM using tickZOOM.
When replaying that data and graphing the bid/ask spread, you see that it has MEANING.
Also, the total depth of market. It's shocking what those things can tell you.
I have come to the conclusion that the reason that people say you need "screen time" (which I have quite a bit) is watching the DOM, Time and Sales, and charts with volume, of course.
With all that information on the screen you can see when the market goes "crazy" or slows down. It kind of breathes.
Well, I committed to building TRUE market simulation much like a flight simulator with full market data, bid/ask, last trade, Time & Sales, and DOM all in tick data.
So you can replay or test historically with a true to live market simulation.
Hey it totally changes the meaning of testing strategies.
I have rules about the the DOM and bid/ask spread change. And that's significant for controlling risk.
Wait, I shouldn't be giving these secrets out in public.
So my theory is that it isn't historical testing per se that is a problem, it's the quality of historical testing that matters.
I'll attempt to prove it with this point.
Successful traders all say you need "screen time" versus historical testing to succeed.
But what if you could go back in time and sit in front of the same screens and charts as that trader did. Then you would learn the same as she did, right?
Well, you can do that with historical data as long as you have COMPLETE historical data.
You can then use historical data to train yourself or your strategies just like the aviation industry uses flight simulators for ground school and the air force uses them for even advanced training.
Sincerely,
Wayne
good first post....