Less uncertainty after earning. LiveVolPro has an option screener. http://www.livevol.com/options-trading-analysis-software It's a premium product. $300/month. Bob
Options are priced in volatility, ie the markets implied range of the underlying. The results of an earnings report is unknown to the market, therefore there is more uncertainty of the future range of the stock. Once the earnings are out, there is less uncertainty, so vol (price) goes down.
This one looks interesting. I have never tried it.I only checked out their website after finding them on Twitter. http://optionsflux.com/pages/faqs
Well i glanced into the site, seems there's nothing new under the sun there.. just selling the most traded options information, nothing you cant find out there, tell me if I am wrong