Quote from Spydertrader:
<img src=http://www.elitetrader.com/vb/attachment.php?s=&postid=1823251>
Data feed went south around the big break time, so on my chart it looked like the YM ran up but ES stayed put for about 10 minutes. That could ruin someones day if on the wrong side.
On a better note, 7 bars earlier in the YM's symmetrical pennant, it broke out higher what seemed like a full minute before the ES moved. ES actually hung on the low of it's bar while the YM broke out higher. - EZ

The above table is based on far too little data (february only). If I post it again I'll do it for more bars and with relevant confidence intervals etc.