As a stock trader, my trading style has evolved over time. However, the one thing that I have always been good at is limiting my mistakes. Book after book I read tells me that I should always cut my losses short and never let a small loss turn into a big loss. I have always been pretty good at that. While I have let 8% losses turn into 15% losses, I made sure that it didn't hurt me too badly by making sure the initial lot of shares I bought was small enough such that a 15% loss would not damage my overall capital too much.
I've learned over time that the market moves against you pretty quickly and the unexpected movements can cause significant pain. I've found that as long as I have not leveraged myself too thinly I can control the pain. I make mistakes when trading such as mistiming an entry point or not getting out early enough, but by taking care of how many shares I buy I can limit the effect of my eventual mistakes before they even occur.
Spam filtering is the same, we need to limit the effects of our mistakes. If spammers are like antibiotic-resistant bacteria, then false positives are like kidney stones. Kidney stones are small but they cause a disproportionate amount of pain compared to their size. We would all do well to avoid them.
I limit my mistakes in stock trading by being cautious about how many shares I buy when I take an initial position. In spam fighting, I limit my mistakes by acknowledging that mistakes (false positives) are inevitable and try to take that into account. The ways I do this are the following:
Those are some of my own personal rules when designing spam strategies. False positives cause an inordinate amount of pain. If 99% isn't good enough for spam effectiveness, then 99.5% isn't good enough for non-spam accuracy. It needs to be incredibly accurate if a system is to be useable in real life.
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> As a stock trader, my trading style has evolved over time.
Well sure. Each time the spammers change their minds about which stock they spam, you need to change your mind about which stock to short ^_^
at which precision level the spam filter is standing when even emails added to safe list can't be reached!
Hotmail filter did this, while returning all OK over the SMTP communiction!!