Hacker News new | past | comments | ask | show | jobs | submit login

Financial predictions absolutely do work. The price of a stock is very well correlated with its future returns. So they're good at predicting how well businesses will do. What they can't do is predict the future stock price movement. But this isn't a failure of financial prediction, it's just an inherent property of efficient markets.

If you opened a betting market on the weather then meteorologists would do no better than monkeys at predicting its price movements.




There isn’t any empirical evidence that they work though. People obviously think it has value, otherwise 22 million people wouldn’t be employed in the business, but any scientific research done on the field has unquestionably shown that financial predictions don’t actually work.

It’s interesting that you mention betting as a counter argument, considering that you’re listening to financial advisors exactly to avoid betting.

Investments is still one of the few places with a positive net gain, unlike betting, so you should absolutely invest. Just know that as far as scientific evidence goes, you’re not better off listening to a financial advisor than you would be by throwing darts at a wall.

Whether predictions, again, is actually the field of predictions where we’re provable correct most of the time, compared to any other field of prediction.

So you’re actually incorrect. If it was possible to bet on the weather forecast, it would be the surest way to make money in the world.

I mean, the fact that you actually can’t bet on whether in a world where you can bet on pretty much everything else, should really tell you everything you need to know.


> There isn’t any empirical evidence that they work though.

What I'm saying is that traders are good at predicting the absolute rate of return of investments but bad at predicting their return relative to their price.

Companies that the traders have valued at $1B actually do make 1000 times as much on average as the companies they have valued at $1M. This is the analogue of meteorologists being good at predicting the weather. But if a single trader says that a company will do better than the rest of the market thinks, then that trader will do no better than chance. Similarly if a meteorologist thinks that rain is more likely than the rest of the meteorologists, then they'll be right no more often than chance.

Asking meteorologists to predict rain but traders to predict relative price movements is an unfair comparison. Either compare the meteorologists' predictions of rain with the market's prediction of absolute profits, or compare the meteorologists' predictions of how much their predictions will change with the markets relative predictions of profits.

> If it was possible to bet on the weather forecast, it would be the surest way to make money in the world.

No, because the person you were betting against would only bet at odds matching the best meteorologists' predictions.


You can repeat yourself, but you’re arguing against scientific evidence.


There is definitely a market for betting on weather. One of the principal components of changes in natural gas and power prices is unexpected changes in weather.




Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact

Search: