My conclusion:
I haven’t found a study or meta-studies that are convinced that technical analysis works
But I agree with ETFOptimizer that to many studies test very simple technical indicators, and tend to test them in isolation. If technical analysis is to work, this must be done together with others to correct for the weaknesses that are inherent in the individual indicator.
I have read some studies that suggest that technical indicators may work on more trending asset classes than stocks, such as forex and commodities,
That said, it is recognized in financial theory that momentum and short term reversal work, so indirectly several of the technical indicators will measure in some way these two, but it probably won’t, in my view, mean that technical analysis overall works very well.
I’v thought sometimes that the reason technical analysis is so popular is first of all that it’s easier to learn and understand than the vast amount of information that needs to be incorporated into fundamental micro or macro analysis. The second is that technical analysis is a bit too easy to manipulate. With small changes in the indicators, they can provide good returns in a backtest, but which in turn makes them so optimized that they are unlikely to provide much value for future prediction of the price action of a stock.
Finally, of the simulations and screens that are available here as “public” , very few use technical analysis alone, and those who do often do poorly.
But I hope more people will publish their results with just technical analysis, so that it will be possible to probe this further.
In any case, if technical analysis is to be used, the simplest indicators cannot be used in isolation, they must be used together with others and it is important that they are not overoptimized.
But there are people in this forum who are way smarter than me, and who have done this “game” much longer, hope they can give some feedback?