The chart below is the spread between the relative strength leaders and relative strength laggards (universe of mid and large cap stocks). When the chart is rising, relative strength leaders are performing better than relative strength laggards. As of 9/12/2011:
RS leaders and laggards have had similar performance for over two years now. However, the RS Spread has been rising in recent months. A meaningful breakout could bode well for relative strength strategies in the coming years.