How Many Patent Claims Are Enough?

In his series on "Evidence Based Prosecution," Professor Dennis Crouch used data collected from patent applications published thus-far in 2006, and compared

the average number of independent claims in a patent application to the total number of claims in the patent. The results fit very nicely to the equation:

y = 0.0921x + 1.1993,

where y is the number of independent claims and x is the total number of claims. The fit has a very high R(^2) value of 0.9967.

His analysis of Sensitivity to Claim Fee Variation also shows the effect of increasing claim fees on reducing the number of claims filed in patent applications around December 8, 2004.