While we do agree that past performance is certainly not a guarantee of future results past performance does provide valuable information.
The stock market will never perform exactly as it has in the past, because on any given day it is very unlikely that all economic variables that effect the market will align themselves exactly as they have in the past. In other words, if we look at any random day it is virtually impossible that at anytime in the future that the economic variables like U.S. inflation rate, GDP growth, unemployment, tax structure, interest rates, import/export balance etc. will ever again be identical to what it was on that date. And if you are basing market predictions on such economic variables, then past performance cannot be an accurate predictor of future performance. By extension then most of the market commentary you hear on TV financial news or read on the internet, are providing useless information in terms of predicting future market performance.
Click the link below to view the entire paper.