dusktrader,

I can agree with almost everything you are saying - and I have my own issues re ranking bots. Where you lose me is when you abstract the bars from the actual time period you are looking at.

1000 240 min bars = 16000 15 mins bars = the exact same history = The exact same time period you wish to have a return in so you can live = the exact same time period that the market changes in.

The types of market changes that make strategies/algos less profitable occur over the exact same periods of years whether you measure them in 240 min bars or 15 min bars.

Implicit in your logic is an assumption that the permanent and cyclical changes you wish to include (or avoid) in your backtesting happen 16 times faster on a 15 min chart compared to a 240 min chart. This does not make sense to me.

I can understand your arguments for less history in general, (I'm not convinced though ;-)), but if you decide that x years is the period you will test for your 15 mins algo, then I think the only valid comparison for the 240 min algo is the same x years.