IBO Speed Ranges?

[konrad]

Most bow manufacturers’ advertising gives IBO speeds as part of their sales spiel. Most of those specifications cover a range (typically 8 fps) or make claims “up to X fps”. Only one company I come to readily advertises a specific number without a range.

Given the IBO specifically states draw length, arrow weight and draw weight, what does this range of numbers represent?

Is this standard deviation, extreme deviation or some other range I am unfamiliar with?

Thanks again,
Konrad

[Lowedog]

I believe that the range is what the manufacturer is saying they found in testing.  I don't believe there is any standard deviation that manufacturers are required to be within.  They can pretty much say what ever they want but from the reading I have done and from testing several bows most of them are pretty accurate.  

Bowtech actually sends a "birth certificate" with each bow that has the actual speed recorded on it at the DL and DW that the bow is set at when it is test fired.