I guess some of you know the news that
Steven Cohen invested in Quantopian. I tried that platform before but i found documentation poor and lack of support. Then I noticed few reports of out-of-sample tests. Has anyone tried it and do you believe it is worthwhile to spend the time to get familiar with it as opposed to using a standard backtesting platform?
I've used it extensively, it is far more powerful than most backtesting platforms I've seen. You can certainly do out of sample tests, you pick the timeframe for every simulated run you do so simply save some out of sample timeframes and after you've perfected/overfitted your algorithm you can test it during another timeframe. It does have some pitfall/limitations:
1. You have to learn at least rudimentary Python. If you've ever programmed anything before it will probably be a couple evenings of self-study before you're up and running. If you've never programmed or don't have an engineering/math/cs background or aptitude this probably isn't for you. The good part is that the more you know the more features you can make use of, while a relatively new person can easily do basic algorithms.
2. It uses minute bars, so no HF trading.
3. No futures, options, or forex, just U.S. equities.
4. It's not designed for chartists, so if you're looking to implement "head and shoulders", "tea cup on a saucer" or the like you're going to need to come up with the underlying logic yourself rather than picking an option from a menu.
I'd say the comment on a lack of support and documentation is very different from my experience. Every interaction I've had with them has yielded an intelligent response by a human, and I've contacted them probably a dozen times. Ironically I'm not paying them a cent and get far better responses than I get from some brokers who I pay quite a bit in commissions to. Their API documentation is better than almost any I've seen, although again you need to know Python or it will be all Greek. They also have a forum where users are surprisingly happy to help newcomers with code and share their ideas and backtests. Obviously few people show successful backtests, but knowing a bunch that failed is also helpful so you don't have to try them yourself. In general the level of sophistication of their users is also far higher than your typical trader bulletin board, so you don't end up with inane arguments about established facts like put/call parity, the definition of Beta, leveraged ETF "tracking error", or the impact of reverse stock splits on an ETN.