Re: Registration 2011
 

A late addition, here is a breakout of the 2010 teams that didn't return this season. The pie wedges are % of all of the 2011 season teams that dropped out.
The bulk (70%) of the dropouts had 4 or fewer years of experience.
The average experience of all 2010 teams happens to be 4.1 years.

P.S.
Here are the dropouts from 2010 and 2009 just so we can see that the trend in dropouts has been gradually shrinking for the 1-year teams over the past three seasons. 3 year teams also dropped a bit this year. Two seasons ago the bulk (70%) of the dropouts had 3 or fewer years of experience.
The 4-year team drop rate tripled this year alongside more modest jumps in the loss of 6 & 7-year teams.

Re: Registration 2011
 

It would be neat to see if any of these teams get restarted next year.

Re: Registration 2011
 

Each year FRC recovers roughly 12% of the lost teams.

Re: Registration 2011
 

Mean or median?

Re: Registration 2011
 

The mean

4.3 is the mean for 2011 season ending teams, i.e., the newest teams are credited with having earned 1 year of experience.

Re: Registration 2011
 

Wow. That would mean the median was somewhere in the 3.6-3.8 range, by my guess. Median would probably be a better measurement of this, because age has a fixed lower bound (rookie = 0 or 1) but no fixed upper bound (except for the 20-year age of FIRST).

Re: Registration 2011
 

The median for both 2010 and 2011 is 4.
The values I'm dealing with are only whole numbers from one to twenty.

Re: Registration 2011
 

I am a little confused, your 2009 and 2010 graphs have an orange bar after the 11 year drop out teams that does not seem to be on the access. 12th year drop out?

The years that make me sad are the 11 year plus drop out team. I always wonder what was the straw that broke the camels back for them.

Making up a causation here: The fact the last large drop out group is the four year group, cause me to wonder if a large hump for teams is recruitment that dries up after the initial freshman graduate?
[I realize that alot of these teams have issues with the other big humps(mentor retention, finances, school support, parent support, ect.), but what fun is data if you don't come to some wild conclusions]

Re: Registration 2011
 

I'd guess it's a combination of student recruitment and money. Our 3rd year was by far our toughest year - since the 2-year NASA grants expired, and we hadn't yet created many strong community partnerships, it was very touch-and-go. Combined with the stresses of being expected to compete at a high level with rather limited experience, I could see a lot of burnout in the 3-4 year range. Once we got over that hump, I woudn't call it "smooth sailing" but we did gain a lot of perspective as a team.
FIRST's culture has historically been to celebrate rookies and seasoned veterans. Although this is starting to change, I can see a lot of 3-4 year teams falling through the cracks, when perhaps they may need the most help of all. (Yes, I realize this has been thoroughly discussed before, but that doesn't make it any less important.)

Re: Registration 2011
 

That's my error in the legend. I deleted 12 from the 2011 legend because it was zero, but then copied the chart to reuse for 2010 and 2009 and forgot to add 12 back on the legend. The orange is as you guessed the 12-year teams who dropped out.

There doesn't seem to be any geographical correlation for the 4-year teams who dropped out in 2011. They are evenly spread out.
It may be related to the original members, including the teacher/advisors/mentors/students, moving on or just looking for a new challenge to get involved in.

Students are involved for ~3 to 4 years, mentors for 5.2 (according to Brandeis) - might be a correlation for people who don't place importance on succession planning - recruitment of students/mentors/teachers/advisors, fundraising for the generations that come after you, leadership & skill transferral, the wearing out of political support.

P.S.
No teams with more than 14 years experience have ever dropped out.