Afternoon vs. Evening Sessions

Yesterday I made the offhand comment that there was no statistical advantage to being in the evening session versus the afternoon session at Nationals. This was based entirely on my own perceptions and a reaction against the general narrative that teams should prefer the evening session because scores increase throughout the day. Well, it's time to put that assumption to the test.

To find how this actually plays out, I looked at the All-Around, which is the only title decided on the first day of competition and therefore is the most relevant to this argument. I took the average of the top 5 All-Around finishers from each session over the last 10 years to see if the evening AAers actually score higher.

Afternoon AA Average - Top 5 Finishers:
2011 - 39.405
2010 - 39.460
2009 - 39.500
2008 - 39.455
2007 - 39.525
2006 - 39.425
2005 - 39.485
2004 - 39.485
2003 - 39.450
2002 - 39.495
Total Average: 39.469

Evening AA Average - Top 5 Finishers:
2011 - 39.385
2010 - 39.495
2009 - 39.540
2008 - 39.545
2007 - 39.490
2006 - 39.440
2005 - 39.595
2004 - 39.600
2003 - 39.470
2002 - 39.495
Total Average: 39.506

Well, there we have it. There does appear to be a slight statistical advantage for AAers competing in the second session. Now, some of these numbers may be skewed by the home team receiving some home scoring in the evening session, but I don't think that alone is enough to account for the difference. It also should be noted that the differences were larger in the past and, over the last few years, the advantage has been statistically minimal or, as in 2011, inverted. In fact, the last three AA winners have come from the early session, including Kupets's massive 39.800 in 2009. The only years where we see a truly notable advantage for the second session were 2004, 2005, and 2008.