Cheers Tim. Im a big fan of focusing on notional size and how it relates to your account when it comes to risk, and really thats about it. I dont like the standard view of RR, % per trade measured from entry to stop etc for a couple of reasons.
i) The standard 'wait for confirmation-take a position-stop out' executes on the side of pa that I dont want to be on.
ii) A stop is where you hope to get out not where you will get out. Any slippage is negative and if youre big enough at the wrong time it can be a killer.
If we take a £10k acc buying a 10k market, at a size that equal £1pp, I see that as 1/1 with a notional trade value of 10k, ignoring costs and reqs for the moment itd take the market to move to 0 for the acc to be wiped out. At £4pp I see that as 4/1 with a notional trade value of 40K. At this size it would take a 25% drop for the account to zeroed. I tarde dax at anything from sub 1/1 up to a max of 4/1. Anything over 3/1 for me is for very short periods, usually managing a position. Most often im 1/1 - 2/1.
If we take the average player who believes big is good and biggers better, hes got his signal and hits the short at £10pp the in the 10k market with his £10k acc. Initial stop is 10pts out (£10ppx10pts = £100... 1% of 10kacc), the first move was favorable so stops to BE and let profits run like a good trader should. The position briefly goes +150 but is still inside the channel hes marked perfectly on his charts, dont wana move stops up too soon like we did last time so gives it room to breath. As the market retraces he consoles himself knowing that the trade is risk free with stops at BE and win some lose some. It shaves the stop and turns back down, "Phew, maybe itll go my way after all".. then whamo, some fat finger-bomb found near christmas market-NPPR surprise bullsh!te-no reason on Gods green earth that I can goes down. He doesnt know where he is cos his screens have froze.. time passes time passes.. tick tick,, opens up his blotter to find -£1900 staring back and the real risk of the trade is revealed.
It doesnt have to be this dramatic ^ and of course it can be a sh!te pile worse, but far more likely the steady accumulation of neg slippage x size can consistently turn that '1% risk' into '1% + a bit more/quite a lot more/are ye feckin serious more' loss.
Jeez, what were we talking about again? Ill put my soapbox away