The three Daily charts below show the Percentage of Stocks Above their 20-50-200 Day Moving Averages. At the moment, they are all above 50%.
In the event that the 6 Major Indices and 9 Major Sectors drop and hold below their middle Bollinger Band on their Daily timeframe, I'd check to see if the percentage on the above referenced three charts also drops and holds below the 50% level. If all three fall and hold below, it's a likely confirmation of further weakness to come in the equity markets in the short, medium, and longer terms...possibly signalling a correction.