Good article about commercially available trading systems

Discussion in 'Strategy Building' started by Sergio77, Jun 12, 2015.

  1. Sergio77

    Sergio77

    Playing with monte carlos will not help you make a dime. Your reaction to this thread shows that you have invested way to much in failed analysis. The point that you failed to understand because of your knee jerk reaction that shows panic is that the author say that you need to develop your own systems because when you buy one you do not know how it was developed. If you wait for 30 trades to do your oversimplified monte carlos you may have experienced already a big loss. Then another one, then another one. When you find a good system with monte carlos you will maybe have no more money. besides monte carlos is stupid analysis. Are you one of those monte carlos analysts? Change your attitude and don't panic.
     
    #21     Jun 20, 2015
  2. IAS_LLC

    IAS_LLC

    Okay.... The point I was making was 30 samples is not enough for a relevant study.. ....did you even read the entire thread, or are your trying to sell PAL subscriptions?
     
    Last edited: Jun 20, 2015
    #22     Jun 20, 2015
  3. Probability of success of 50% doesn't mean that reward:risk is 1. What about if reward:risk is 5?

    Also, what about if the system does trend-following? Does the MC make any sense?

    "Set up a a monte carlo study that results in 15 entries uniformly distributed across the day, with holding period statistics that match your trades."

    What does it mean to "set up a monte carlo that results in 15 entries uniformly distributed"?

    OK, you are making some statements I'm not familiar with. Please elaborate.
     
    #23     Jun 20, 2015
  4. IAS_LLC

    IAS_LLC

    Correct, but the risk:reward is irrelevent. All the monte carlo simulation is seeking to determine is if the returns produced by the "system" during backtest are likely or unlikely to have been produced by random chance. A market model isn't being varied, entries and exits are.


    I dont do trend following, but I think you should still get value out of it. If your trend following system is getting lucky, its likely random entries will to. You could even set a trend bias as monte carlo paramter (e.g 80% of entries should be long, +/- 10%...etc).

    Lets say your system produces an average of 15 entries per day (normally distributed, +/-3 trades 1 Sigma), and has an a average holding time of 5 minutes (laplacian distributed +/- 1 minute 1 Sigma). A monte Carlo simulation to establish confidence that your backtest returns were not produced by chance could look like this, for each day tested:

    1. Set Random Number Generator Seed
    2. Based upon system entry statistics, generate 15 (or so) entry times that are uniform-randomly distributed across the entire trading day.
    2. Based on holding time statistics, generate holding periods for each trade
    3. Backtest the trades with the same market data that the system was tested with.
    4. Repeat for a new random seed.
     
    #24     Jun 20, 2015
  5. See my response in the other thread about your other test. This test is also irrelevant if it is based on results from a backtested curve-fitted system. Most random systems will rank inferior to the curve-fitted system. Your true null hypothesis here is:
    H0: Backtest returns are better than random returns
    H1: Backtest returns are worse than random returns

    As you can see if the backtest returns were curve-fitted to price series there is a high propability of Type I error.

    I think you have to go back to drawing table. Your tests are based on misconceptions.
     
    #25     Jun 20, 2015
  6. IAS_LLC

    IAS_LLC

    Of course it is prone to curve-fitting, data snooping, and other biases. I guess I didn't explicitly state that the simulation should be done on out sample data, but I figured that was implied.... guess not.

    You seem to have a lot of opinions on what doesn't work... I'd love to hear what does?
     
    #26     Jun 20, 2015
  7. Those are not opinions. They are facts based on established statistics. Note that you wrote:

    So do I read this right or did you write one thing and you meant another? You talked about tests based on backtest results. All tests on backtest results are useless and tests on real results may be too late as someone else already mentioned. You have limited choices and nobody will tell you what works. You should be grateful that some people are willing to help you correct your mistakes. These mistakes are too basic.
     
    #27     Jun 21, 2015
  8. Sergio77

    Sergio77

    http://www.elitetrader.com/et/index...ng-study-resources.201826/page-4#post-4139471

    Just be careful you may be accused by him for promoting a website or book. I doubt he understands one word of what you said. He is busy flipping coins.

    Thanks for the clarifications anyway. Very useful stuff to me at least.
     
    #28     Jun 21, 2015
  9. Sergio77

    Sergio77

    I'm going to post links to useful websites that protect people from your likes no matter your intimidation efforts.

    Here is another one for you and the vendors that design these stupid monte carlos tools:

    http://eranraviv.com/multiple-testing/

    This should teach you proper statistics and also tell you that the tools you may be promoting do not work.
     
    #29     Jun 21, 2015
  10. IAS_LLC

    IAS_LLC

    Okay, so you are saying there is no value in back testing?
     
    #30     Jun 21, 2015