AP Photo/Richard Drew AP For this month, the cycle/relative strength concept is applied. First, the S&P 500 stocks are ranked from the best performer to the worst by calculating the expected return in that month. The top best traditional performers in the month were then screened for relative strength by a unique measure that sorts by several relevant time periods. Those that pass both screens are buys for the month. The stocks that are both weak monthly performers and weak relative performers are short sal ...