Quote from patrick_newB:
Let me try to add something to this thread. Acrary in one of his very insightful posts talked about "drag" that can be introduced in an equity curve by reducing trade size after losses. As a result I always keep my trade size constant until after a new equity high, when I am free to increase or decrease my size. The basic premise is that if you go for a 10% profit target and a 10% stop, and you base your trade size on your equity you can introduce "equity drag" into the equation like so: (alternating 10% losses followed by 10% wins).
10,000
9,000
9,900
8,910
9,801
8,821
9,703
8,733
9,606
8,645
9,510
8,559
9,415
8,473
9,321
8,389
9,227
8,305
9,135
8,222
9,044
By keeping trade size constant you end up with 10,000 at the end of this series instead of 9,044 - which in my book is a big difference. By keeping trade size constant you do increase your risk after a loss. I haven't found a good justification for increasing trade size after a loss but I'm comfortable keeping trade size constant after a loss or series of losses to avoid the "equity drag" phenomenon.