Advancers led decliners by almost 3:1 today on the Nasdaq and almost 5:1 on the NYSE.
In the book How Markets Really Work, tests run from 1989-2003 show that a bullish advance/decline ratio is actually bearish for the markets over the next week.
Here are some charts from the book that illustrate the quantitative disadvantage facing the bulls over the next week:
The chart below shows that the A/D combined with the 200 day MA points to the possibility of even more downside, over the next 5 days.
Be aware that I have not seen the results of these tests over the past 5 years. Any edge may have been diminished or eroded entirely over this time period.