Patent Law

By David Schwartz

How do district court judges with varying levels of experience perform on claim construction?  Are judges more likely to have their decisions affirmed when they have previous claim construction experience?  Previously here and here I provided some background on the large database I compiled and some of the results.  A draft of the paper, Practice Makes Perfect? An Empirical Study of Claim Construction Reversal Rates in Patent Cases, can be downloaded here.

Today’s post provides an analysis of the data based upon two measures of district court judge experience: (1) the size of the district court judge’s total patent docket over an eleven year period; and (2) the performance after a first reversal by the Federal Circuit.  As for the first measure, I determined the reversal rate (as measured by cases in which an incorrect claim construction required the case to be reversed or vacated) based upon the number of patent lawsuits a district court judge was assigned.  Figure X below illustrates the results.

Figure X shows that the claim construction reversal rate varies little with the total number of patent lawsuits handled. The reversal rate was between 26.7% and 34.1%.

I turn now to the second measure of experience. It may be that a district court judge pays little attention to a Federal Circuit opinion if the case was affirmed. In contrast, when the result of a case is affected, the district court judge takes note. A remanded case is often returned to the same district court judge for further proceedings. As these further proceedings are time-consuming, the district court judge likely will remember the opinion remanding a patent lawsuit to his or her docket. Figure N below illustrates the reversal rate on all subsequent claim construction appeals after a particular district court judge has been reversed or vacated at least once due to an erroneous claim construction.

Figure N shows that the first reversal does not have a significant effect on the future performance of the district court judges, with the rate the varying from 25.0% and 44.4% for reversals, and from 31.4% and 44.4% for errors. The percentages in this breakdown vary to a greater degree than the percentages based upon number of prior appeals (reported yesterday).  However, the trend is not linear and the differences among the judges illustrated in Figure N are not statistically significant. 

The data illustrated above and described yesterday do not suggest that district court judges learn from having their claim construction rulings appealed.  As I explain in more detail in the paper, there are many possible explanations for the surprising results.  Three likely explanations are (i) that claim construction is inherently indeterminate; (ii) that district court judges are incapable of or not interested in learning how to perform claim construction; and (iii) that the Federal Circuit decisions do a poor job of teaching district court judges how to construe claims.  (Another possible explanation is that limitations in the data, as described in detail in the paper, affect the results.)  If the indeterminacy explanation is correct, then it will be difficult to lower the claim construction reversal rate, especially as long as those decisions are reviewed de novo.  If the district court judge explanation is correct, then a primary rationale for adopting the Issa patent pilot program is likely faulty.  In other words, if district court judges cannot learn how to perform claim construction, creating quasi-specialized patent judges is unlikely to reduce the reversal rate.  If the Federal Circuit explanation is correct, then the Federal Circuit must redouble its efforts to create a uniform body of claim construction case law.

For those who are interested, the paper also analyzes the data based upon various other characteristics of the district court judges including age and years of judicial experience.

I’d like to thank Dennis for permitting me to share my results with the readers of Patently-O.  I’d like to also thank the readers of Patently-O for their comments.