Another interesting content about calculating estimated ROI for a specific site and body of keywords posted by Shannon Skinner form the Moz blog site. In this story we gather data from the keyword, strength of your preferred URLs, competition URLs by keyword, strength of competition URLs, then analyze the data by keyword and calculate your potential opportunity. Kindly visit this link for your reference and take time to analyze this content and compare in your experience then let see if we have some effective method to pick up. Calculating Estimated ROI for a Specific Site & Body of Keywords - Moz