Re:Introduction to Zipline: A Trading Library for Python
by gedrap on Tuesday July 26, 2016 @03:34AM
(#12163910)
Agreed. Probably a large fraction of 'profitable independent day traders' mention by parent depend on luck. It's one thing to post a profitable month/year, whole different thing is a profitable decade.
It's relatively easy to have a profitable period on a strongly bull market. But it's irrelevant if any 'unexpected' (people call such events unexpected despite the fact that they tend to happen regularly over time) event such as 2008 crisis will completely wipe you out.
There's actually a logical error here: if trading results were essentially random, a certain subset of traders (including day traders) would, at any given time, have profitable records. But you would not be able to derive (and, therefore, implement in code) any set of rules which would make automated trading profitable. You would just either be lucky, or not, as an algorithmic traders just as you would as any other kind of trader.
Now, I'm not saying that trading profits are random, but the existence of some profitable traders does not mean that there are rules you can deduce from their behavior that will guarantee profitable trading when implemented by someone else (either in an automated system or otherwise.)