“It should pay a dividend”

Warren Buffett says that if a company can generate 10 cents or 20 cents by keeping a dollar, then it should keep it (invest in growth) . If it cant, then it should pay it out as a dividend (value). What is the best way to know how much a company is generating on the dollars it retains? Im thinking along the lines of ROE? ROIC? Someone with better fundamental analysis skills help me out please.