Everyone keeps saying "data." But, he said that there were obvious errors. Sounds to me that the backtesting system is not back-trading as he expects it to with the data given; regardless as to whether that data is bad or good. Given the same data, good or bad, I would expect a backtesting system to come up with the same results that I do by manually testing some of the data. I expect different backtesting platforms to have the same results if using the same data--good or bad. And, don't these platforms provide their own data? If so, then it doesn't matter if it's the platform's data, or the software that's the problem. He's looking for something more reliable regardless as to which is bad.
You can circumvent bad data with programming if the errors are consistent and easily detectable. Now if you have wrong values that aren't wrong enough to be detected, you're out of luck.
Yes, programming is going to be involved, or course. But you also need data from other sources. For example, how are you going to fix this with just programming: Open=20, High=23, Low=21, Close=22 It's an obvious error--as you required. But how would you fix it? Without additional data, you can only GUESS at what it should be, maybe it'll be "fixed;" maybe not. Is the Open wrong, or the Low wrong? How do you know?
That works. (But in some systems, one bad bar will 'corrupt' several surrounding bars). You could also guess by analyzing the surrounding data. I guess I just wanted it to be clear that none of these work-arounds actually 'fix' the problem of initially obtaining bad data.
Did you submit a thread about your findings of error on the MC forums ? They have superb tech support. I would be very surprised that no one else discovered the same errors. Exactly what "errors" did you find ?