How do district court judges with varying levels of experience perform on claim construction? To study that question, I compiled a large database that includes every single post Markman Federal Circuit decision involving claim construction. Others have studied this issue from the perspective of the Federal Circuit --- i.e., what is the overall reversal rate. However, until now, no one has analyzed how district court judges perform based upon experience. My findings do not reveal any correlation between various measures of experiences and the likelihood of being affirmed. There will be several posts on the study and results. Today, I will provide some background on the dataset and a bit on the reversal rate. A draft of the paper, Practice Makes Perfect? An Empirical Study of Claim Construction Reversal Rates in Patent Cases, can be downloaded here.
The Dataset. First, a few brief words about the dataset. The dataset includes all decisions in which the parties disputed an issue of the district court's claim construction. It includes all decisions in an eleven year period, from April 23, 1996 (the date of the Supreme Court decision in Markman) until June 30, 2007. Those decisions – 952 of them – are all of the published and unpublished opinions, as well as all of the summary affirmances under Federal Circuit Rule 36.
Overall Reversal Rates. For the entire eleven year period, 38.2% of cases had at least one term wrongly construed. Moreover, 30.0% of the cases had to be reversed or vacated because of an erroneous claim construction. These results are largely consistent with those of an earlier study (by then-professor and now-Federal Circuit judge Kimberly Moore).
Reversal Rates by Judicial District. In later posts, I will present the reversal rates based upon the experience of the district court judges. Today's post presents the reversal rates aggregated by judicial district. Table II below identifies the number of Federal Circuit appeals from the most active judicial districts in terms of claim construction appellate decisions from April 1996 until June 2007. It also provides the percentage of cases that were vacated or reversed due to an erroneous claim construction. In the last column, I have provided the total number of patent lawsuits filed in those judicial districts, and in parenthesis, the rank of the judicial district if measured by the total number of patent lawsuits filed.
Table II: Most Active Judicial Districts on Appellate Claim Construction Experience: 1996-2007 | ||||
Rank |
Judicial District |
# of Federal Circuit Claim Construction Appeals (1996-2007) |
% of Claim Construction Appeals Reversed or Vacated because of Claim Construction Error |
# of Patent Lawsuits Filed (1995-2005) |
1 |
N.D. Cal. |
84 |
28.6% |
2613 (1) |
2 |
C.D. Cal. |
69 |
43.5% |
2260 (2) |
3 |
N.D. Ill. |
65 |
26.2% |
1509 (3) |
4 |
D. Del. |
54 |
22.2% |
1112 (5) |
5 |
S.D.N.Y. |
45 |
28.9% |
1184 (4) |
6 |
D. Mass. |
42 |
26.2% |
782 (7) |
7 |
D. Minn. |
33 |
36.4% |
743 (8) |
8 |
E.D. Mich. |
29 |
31.0% |
669 (9) |
9 |
D.N.J. |
28 |
32.1% |
952 (6) |
10 |
E.D. Va. |
27 |
22.2% |
555 (14) |
11 |
N.D. Tex. |
21 |
42.9% |
591 (11) |
11 |
S.D. Tex. |
21 |
23.8% |
466 (19) |
13 |
W.D. Wisc. |
19 |
21.1% |
232 (36) |
14 |
W.D. Wash. |
18 |
38.9% |
475 (17) |
14 |
D. Col. |
18 |
27.8% |
407 (23) |
As is evident from the Table above, several of the busiest districts have reversal rates above the average rate of thirty percent. For example, the second busiest district in the country, as measured by either number of appeals or number of patent lawsuits handled, the Central District of California, has the highest reversal rate of claim construction. (Some may wonder why the Eastern District of Texas is not included in Table II. The trend of filing cases in the Eastern District of Texas began fairly recently, and as a result, many of the cases from the Eastern District of Texas have not had time to proceed through appeal. Consequently, the Eastern District of Texas is not one of the top fifteen districts in terms of appellate claim construction experience during the period 1996-2007.)
Up next: Reversal rates based on the number of claim construction cases previously appealed (i.e., the first case appealed from a particular district court judge, the second case appealed from a district court judge, etc.)
Comments are welcome!
