Before I had decided to run in the Bay State Marathon, I was considering running in the Cape Cod Marathon. The CCM is one week after the BSM, so they are both at the perfect time of the year here in New England for marathon running.
I ended up choosing the BSM entirely because it is very close and convenient to where we live, in fact part of the race is in our town.
Partly as a result of almost running the CCM and that it was only a week after my run, so I still had marathon running on my mind, I was interested in seeing the results.
2008 Cape Cod Marathon--899 finishers, 20th percentile time 3:41
2007 Cape Cod Marathon--1006 finishers, 20th percentile time 3:33
2008 Bay State Marathon--1195 finishers 20th percentile time 3:19
2007 Bay State Marathon--717 finishers 20th percentile time 3:24
Observations:
1. The CCM is smaller this year than last, while the BSM got bigger this year.
2. The BSM is faster than the CCM.
3. In both cases, the larger field had faster times.
Here is my all-purpose hypothesis. This year, the BSM was selected as a New England championship race. This would account for the larger field this year as well as the faster times. It may be that we can divide runners into elite runners and local runners (there is lots of overlap between the groups). So when a field is larger or smaller than normal it is due to the presence or absence of the elites. The elites are by definition faster and so a large field gives a faster times.
Update: I am tempted to run the Cape Cod next year since it would be fun to place in the top 10% (as I would have this year with my time in the BSM), instead of the top 25% in the BSM. On the other hand, the CCM course might just be a lot harder; if I placed at the 25th percentile in it this year, I would have missed qualifying for Boston by 15 minutes.