mandynshane wrote:
It either works or it doesn't, right?
Well, I think there is more to it than that.
Things can work well for long periods and then one day they just stop working, and you discover then that you were just observing what appeared to be patterns in a basically random set of data.
Backtesting tells you if something work
ed at some point in the past. When you have a strong theory to go with your backtesting results, however, it can provide you with a stronger basis for anticipating what future performance might be expected to look like.
As Harry Browne said, we don't use backtesting to prove a thesis, we only use it to
disprove a thesis. With the portfolio you are describing, it doesn't sound like there is any real economic theory behind it other than it consists of assets that have played well together in the past. These relationships may or may not continue into the future.
I like the PP because it basically defines all possible economic environments that may show up in the future (including the likely and unlikely ones) and provides a way for me to invest safely without having to make any correct predictions.