Quote "Hanover" from forex factor
http://www.forexfactory.com/showthread.php?p=3116534#post3116534
hanover
Commercial Member
Member Since Sep 2006
3,322 Posts
OK then let's do this topic to death all over again........
No betting system, including Martingale, offers any advantage in expectancy over flat betting, over any number of trials (trades). Prove the laws of math wrong, by using the attached XLS. Go on, you know you want to! Type any combo of values into the yellow cells that result in the gray cell (AK8) having a non-zero value, and re-post the XLS here. Then ready yourself to accept the relevant Nobel prize. (all assuming there are no bugs in the XLS formulae )
Let's apply some common sense. If it were possible to gain any kind of edge at roulette by varying bet size, everybody would go down that path, and casinos would be forced to change the game mechanics. It's not just the table limits that restrain you. Sure, they're there to protect the casino against a freakishly lucky punter, but even without those limits Gambler's ruin would ensure that virtually every punter who doubles up repeatedly will end up bankrupt long before the casino does.
Similarly, if it were possible to win at forex by using MM (i.e. varying position size or method) alone, then surely every trader would go down that path, and become a millionaire. The 'willing-buyer, willing-seller' and zero sum game constraints provide proof that this is an impossibility.
Averaging down will give you +EV to whatever extent the probability of price reverting to a mean improves, the further it trends away. Increasing one's bet size as probabilities improve is smart (ask any Blackjack pro). But increasing one's exposure without limit is guaranteed to eventually result in irretrievable drawdown.
Here's the rub. Let's say we average down, doubling our pos size every 10 pips. If price moves 80 pips against us, that's 1+2+4+8+16+32+64+128 = 255 units at risk. So we need odds of 255 to 1 in our favor that price will reverse 10 pips, before it falls another 10, to justify that bet size. The problem is that our bet size is based on our desired account balance, and is no longer commensurate with the probability that's being offered by the market.
And let's not forget that costs must be overcome. With a 2 pip spread, you'd need price to move 12 pips in your favor (TP) before it moves 8 pips against you (SL).
Ironically, Martingale guarantees a 100% win rate, until you lose everything. The only consolation is that the losing sequence that causes the 'death trade' might not happen during your lifetime. Irony #2 is that the longer you live, and the more often you trade, the greater the probability that you'll encounter it. There might be several hundred chambers in the gun, but you never know which one holds the bullet. Maybe it won't happen until the year 2030. Or maybe it will happen next week.
There are lots of ways to mitigate the effect of the Martingale:
1. You can use a less severe betting progression (e.g. Fibonacci steps, d'Alembert, etc), but then it takes more than 1 win to return to breakeven, i.e. you cripple your recovery rate. You need multiple wins without intervening losses, making recovery more difficult. So you're effectively offsetting one type of risk with another.
2. You can start with a nanolot pos size, but then your return is reduced in proportion with the risk. Not much point in having a $10k account and winning only 10 cents per trade. (Then, after (say) 10 losses, having to risk $204.80 just to make 10c!)
3. You can cut your losses and start over, e.g. after 5 losses, but then you're back to sizing at 1 unit, so you'll need 1+2+4+8+16 = 31 consecutive wins just to recover to breakeven. Or after 6 losses, you'll need 63 consecutive wins. And so on. Just another way of crippling the recovery rate.
4. You can withdraw winnings from the account periodically, but in doing so, there's less funds there to provide a buffer against a prolonged losing streak, thereby increasing the probability of a margin call. And there's no guarantee that you'll make the withdrawal before the death trade occurs.
The conclusion is: In any activity that involves uncertainty, return is always somehow commensurate with risk. To assure a 99.99999% win rate, you have to take an 0.00001% risk of losing everything. The innate, perfectly balanced equilibrium ensures that there's no exploitable loophole, no free lunch.
Anybody can get lucky in the short term. And maybe more than once. But I assume that most folk here aspire to be traders rather than gamblers. Having said that, there's no law against using forex as a vehicle to gamble, and with more leverage than any casino will ever offer you, should you choose to. Good luck!
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Quote from buybig:
Hello, folks.
comments to this thread --> http://www.elitetrader.com/vb/showthread.php?s=&threadid=147017 led me to wonder a few things.
1st some comments:
"I think averaging down is like cheating on your trades."
"Averaging Down is an unavoidable disaster if the trader does not implement proper planning and preparation."
"In the right hands with the right methods it's a very powerful money management technique."
"Only those in the dark blow up with it. Sadly, the vast majority of the traders fit the "in the dark" profile."
"Second that. It's an "advanced" technique and should not be used by a novice trader that doesn't apply appropriate money management in his trading."
"never ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever ever average down"
"Averaging down is not always disastrous if used in the context of investing when you are building a position."
on to the questions:
1) it seems the consensus is to NOT average into a loosing position. but people in the know can do it successfully. So for those in the know what is a general frame work to work within?
2) lots of general statements but, wouldnt avergaging down be related to risk tolerance, bank roll, defined stop and most importantly LEVERAGE and time to hold?
3) do stocks vs options vs futures averaging operate under different parameters?
4) the question im dying to know is a framework for averaging UP. Given a set stop loss w/ NO avg down.
sure i could go on forever. been on this forum for a while and never really heard ANYONE say how to do it successfully. Just that it can be done by few successfully. If so, please enlighten.

SIDENOTE: I have averaged down in the past and came out ahead. BUTTT it scared the hell out of me.. Tried it a 2nd time lost a bit but used my SL. What really hurt me was saying "the market cant sustain this rally" DOH..