We Are Looking at the Vanguard Study

日期:2012/11/27

We are looking at the Vanguard study that mentions Shiller favorably and it's obviously flawed. The overlap, part whole correlations, and selected starting and ending points, as well as the intrinsic illogic of a 10 year horizon forecasting well but not a 1 year which means that the previous 9 years were much more predictive than the last year, or that the last 5 years are correlated differently from the prior 5 years, comes to mind. But of course, the lack of degrees of freedom with 10 year data with all the overlap, to say nothing of the historical data that Shiller uses, which is retrospective and not reported at the time. But of course one hasn't read it yet, and they purposely make their methodology opaque wherein one could have found the real problems with it.