pic: FRC Growth vs Attrition - All Years

[rick.oliver]

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[prensing]

OK, I am a little confused. For 2013-2016, the rates look to be pretty much identical and in fact attrition is higher in 2014. That means that the number of teams should be flat. Yet in a different graph submitted by Mr Oliver, the total number of teams has climbed steadily, except for 2005.

What am I missing here?

[Alan Anderson]

I think you are trying to interpret "growth rate" as "new teams". In at least one earlier set of numbers, "growth" was actually "net growth" and already included the effect of attrition.

[prensing]

Yes, I realized that a little later. Sorry, but to me, you should never plot those numbers on the same graph. If you graph something, especially something like percents, and on the same axis, they should have the same base. So, plotting new teams vs teams who drop out would have been much more understandable (my opinion ;-).

[GeeTwo]

Originally Posted by prensing

OK, I am a little confused. For 2013-2016, the rates look to be pretty much identical and in fact attrition is higher in 2014. That means that the number of teams should be flat. Yet in a different graph submitted by Mr Oliver, the total number of teams has climbed steadily, except for 2005.

What am I missing here?

The definition of growth and attrition. Based on my earlier looks at these numbers*, I believe that "growth" has already had attrition subtracted, so that "growth" should be called "net growth".

Making the same assumptions as to the data source, the info up to about 2002 is not dependable because TBA does not include full event information for events through 2002, only those who received awards are reflected.

I also understand (from a Sean Lavery post, IIRC) that the 2005 dip is at least partly due to some missing event information from 2005.

* I'm presuming that this is based on the data from TBA re-posted here.