Do “fuzzy” Software Patent Boundaries Explain High Claim Construction Reversal Rates?

Bessen and Meurer (2008) theorize that a breakdown in notice of patent boundaries caused the patent litigation surge of the 1990s. They argue a prime source of this breakdown was the proliferation of software patents with particularly uncertain scope. In this paper I seek evidence that software patent scope is more uncertain by extending the empirical literature on claim construction reversal rates to determine whether the Federal Circuit has been more likely to find error in district court construction of software patents. Not only do I find that it has, I find that over the last decade software patents account for over one third of the difference between the Federal Circuit’s high claim construction reversal rate and its lower average reversal rate on all other patent issues. These results are cause for optimism in that in general the application of existing claim construction law is more predictable that has been feared. However, this optimism does not extend to software claim construction, which is highly unpredictable. Miller: “Fuzzy” Software and Claim Construction Reversal 1