I think you're tugging a lot more. I don't think that most people can estimate anything beyond "this earnings call makes the price go up or down [a little/lot]". I'm not referencing some missed arbitrage opportunity, just that general stock movements can likely be predicted before earnings calls for well-reported companies.

People with insider trading knowledge don't seem able to accurately predict the exact price, but they know if its good/bad/great news and how wall street reacts to that .