Timing the Market with Mean Reversion Indicators

Investors are enamored with various investment houses and personalities who claim insight into the prospects for long-term expected market returns. Some classic examples include Nouriel Roubini, John Hussman, David Rosenberg, or Jeremy Grantham. All really smart people. But have you ever asked "How" these folks came to their conclusions? In most cases, the answer is probably "No" and the reason is because there is a lack of transparency from the author(s) and/or a lack of knowledge/understanding on behalf of the reader. We also want to highlight that one can develop incredibly complex return forecasting models -- super sexy, super interesting, super compelling, etc. -- but that still doesn't mean they are any good at forecasting much of anything.