The downside to this method is it isn't a good guide to future performance. (investopedia.com)
The letter says that the grades obtained provide a better guide to future performance of students as Cambridge undergraduates than other methods of selection, such as GCSE results — which are «nowhere near as reliable» - or aptitude tests. (bbc.co.uk)
Efficient diversification will not be enough to earn good returns; even very well established track records will provide a less reliable guide to future performance; and bond managers will probably have to stray far from their comfort zone to deliver even modestly positive real returns. (businessinsider.com)