The following list provides the most-often cited cases in BPAI decisions thus-far in 2011.

The vast majority of BPAI decisions involve a patent applicant appealing an examiner's final rejection and the most common patentability issue on appeal is obviousness. Thus, it is not surprising that many of the cited cases involve obviousness and claim construction issues. These cases have influenced the court in the past and are likely to continue to do so.

1. KSR v. Teleflex, 550 U.S. 398 (2007) (Standard for obviousness);
2. In re KAHN, 441 F.3d 977 (Fed. Cir. 2006) (Reasons for obviousness determination must be articulated);
3. In re AMERICAN ACADEMY OF SCIENCE TECH CENTER., 367 F.3d 1359 (Fed. Cir. 2004) (Claims should be given their broadest reasonable interpretation);
4. In re OETIKER, 977 F.2d 1443 (Fed. Cir. 1992) (The examiner has the burden of presenting a prima facie case for rejection);
5. Graham v. John Deere, 383 U.S. 1 (1966) (Methodology for determining obviousness);
6. In re Keller, 642 F.2d 413 (C.C.P.A. 1981) (A rejection premised upon a combination of references cannot be overcome by attacking the references individually);
7. In re Morris, 127 F.3d 1048 (Fed. Cir. 1997) (Claims should be given their broadest reasonable interpretation consistent with the specification);
8. Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (ordinary meaning of claim);
9. In re Merck, 800 F.2d 1091 (Fed. Cir. 1986) (Non-obviousness cannot be established by attacking references individually where the rejection is based upon the teachings of a combination of references);
10. In re Best, 562 F.2d 1252 (C.C.P.A. 1977) (When the PTO identifies prior art that is the same or substantially the same as claimed subject matter, the burden shifts to the applicant to come forward with evidence and argument showing that the prior art products do not necessarily or inherently possess the characteristics of the claimed product);
11. In re Zletz, 893 F.2d 319 (Fed. Cir. 1989) (Claims must be interpreted as broadly as their terms reasonably allow but limitations should not be read into claims);
12. In re Schreiber, 128 F.3d 1473 (Fed. Cir. 1997) (claim structure form primary claim limitations; elements of anticipation);
13. In re Spada, 911 F.2d 705 (Fed. Cir. 1990) (process of proving anticipation);
14. In re Gurley, 27 F.3d 551 (Fed. Cir. 1994) (Teaching away; A known or obvious composition does not become patentable simply because it has been described as somewhat inferior to some other product for the same use); and
15. In re Warner, 379 F.2d 1011 (C.C.P.A. 1967) (The PTO must produce factual basis for its decisions).

To create the table, I first parsed all of the BPAI decisions that have been released thus far in 2011 in order to create a table of authority for each case. I then ranked the cited cases to find those that were most-often cited.

As an interesting tidbit, I also looked for correlation between the citation of a particular case and the outcome of the BPAI decision. As you might expect, some cases are better for patent applicants. Two examples of this are In re Warner and In re Gurley. In cases citing Warner, the examiner's rejections are affirmed less than 10% of time. On the flip side – cases citing Gurley affirm the examiner rejection in more than 80% of cases.