My system works just fine during last 5 years, including the bear market. However it doesn't produce good results when I run it during 1990-1998. Does it really matter that my backtesting doesn't work far back, but works during last 5 years and has over 500 trades? Anybody had similar experience? Since volume was different in 90th and some stocks are not even trading now then can one really judge current system on past results 10 years ago?
I would spend some time studying the markets and then determine how well the current market conditions mesh with the markets that the system performed well in. Today's market is nothing like the market of 2000 and 2001 and early 2002, IMO.