I would be curious about your thoughts on the interaction between a runner's age graded index (AGI) and the Boston qualifying time for the age groups. My analysis indicates that the is about 66-67% for the younger brackets and then drops to 63-64% starting with the 60-64 age bracket. A few percent doesn't seem like much but it is actually a big deal. Part of the trend towards older runners may be because it is actually significantly easier to qualify for Boston as an older runner. Can't get in to Boston? Wait a few years then. For example, I am 62 and just barely qualified for Boston this year and last wherein the standard was 3:50 (64.94% AG I) but at ages 55-59 I hadn't a prayer of meeting the 3:35 standard (66.31% AGI). Similarly, I am greatly looking forward to turning 65 when I anticipate very easily meeting the 4:05 standard (64.03% AGI.)