RE: Sell offs..30 Jul 2023 20:50
LLL, I don't believe there is any contradiction here.
1. My claim is that if you say something like "XYZ pattern is a buy signal", then to lend evidence to the claim, you need to backtest it on past data. To clarify, a valid backtest here would be a necessary, but NOT sufficient, condition for the claim to be true. It could be that the pattern existed in the past only by random chance, and there is no such reliable pattern going forward.
2. The FT article (correct me if I'm wrong) seems to be claiming that backtests are not a reliable way to make money, i.e. any patterns you discover in a backtest will not be reliably played out in future price movements. Could you let me know if you still think this contradicts the first claim?
To be extra clear, DSM's claim was that you can say "XYZ pattern is a buy signal", and not even analyse past data (the necessary condition) to even check that it has made money in the past, let alone will do in the future.