Why trading before an earnings report is a risky gamble

I've seen too many traders try to trade something on a hunch because they thought earnings were going to be a blowout. It's much more complicated than that. There's the EPS, top-line growth, expenses, one-time charges, and forward-looking statements that get reported. I've seen companies beat by $0.02 per share, but the forward-looking statements are bearish or cautious and the stock sells off. Trading on hunches is a gamble: you don't know the probabilities nor the expected values. If you can't model it, you can't trade it.