Data is supposed to be at the heart of the modern investment process. Investors and researchers worship at the altar of data of all sorts that could possibly have an impact on their investments. And its not just business and economic numbers. The domains from which supposedly relevant data could possibly originate are indeed numerous. It could be demographic trends, or weather phenomena like El Nino, and even the results of global sports events, as we are being told nowadays. Not just that, a recent article in The Economist claimed that cold weather helps the stock markets, after noting that hot weather was already known to do so!
However interesting they may be, poring over temperature and rainfall graphs of data over decades will not help anyone make better investment or even business decisions. In fact, the abundance of data of all sorts actually creates a problem. It allows data to be found that can support almost any conclusion. This is quite obvious when you read or watch some 'research' based on such data. The analyst has clearly started with a conclusion and then gone about hunting down data that can prove the conclusion.
A close relative of this is the activity of looking for cause-and-effect in things that just happen to be correlated. While this is far more common in health and science articles, but business and investing are not immune to it. In fact, there's a website, tylervigen.com, that is dedicated to spurious correlations. Did you know that over the last 15 years, there has been a strong correlation between the number of people who drown in swimming pools every year and the number of films that the Hollywood actor Nicholas Cage has acted in during that year? Cause and effect? Perhaps not. But then, is the connection between cold weather and stock prices more plausible, or does it merely appear to be so.