Last week a friend complained to me about an obviousness rejection that cited 8 references. In the spirit of Thanksgiving, I told him to be thankful that he was not prosecuting 13/565,966:

Claims 1, 2, 6, 8—17, 36 & 71 are rejected under pre—AIA 35 U.S.C. 103(a) as being obvious/unpatentable over either Obenauf et al (4,502,035) or Campman (5,317,305) or Kaufman (5,857,939 or 6,251,048 or 2002/0028730 or 6,582,342 or 2003/0171189) or Delman (6,179,746 or 6,244,988) or Ohsuga et al (2001/0001303 or 6,244,987) or Loveless (2003/0215777) or Rast (2003/0216228) or Ellis et al (2004/0102931 or 2004/0215958 or 7,670,263 or 2010/0056340 or 2010/0056876 or 2010/0062740 or 7,905,815 or 8,251,875 or 8,452,259 or 8,795,137) or Grober (2006/0063600 or 7,160,200 or 2007/0111811) or Noble et al (2007/0015611 or 7,383,728) or Asukai et al (2007/0060446 or 8,858,453) or Dugan (2008/0085778 or 2010/0130298 or 8,337,335 or 2013/0095940 or 8,430,770 or 2013/0184841 or 2013/0184843 or 2013/0190906 or 2013/0190907 or 2013/0190908 or 2013/0225335 or 8,808,102 or 8,808,114 or 8,579,767 or 8,652,010 or 8,694,136 or 8,725,276 or 8,923,998) or Vincent (2009/0048070 or 2009/0233770 or 7,927,253 or 8,221,290) or DiBenedetto et al (2010/0292050 or 8,241,184 or 8,562,490) or Oleson et al (8,033,959 or 2012/0028762 or 2012/0274469).

or 14/947,476:

Claims 4 and 5 are rejected under pre-AIA 35 U.S.C. 103(a) as being unpatentable over Porteus (Mol. Ther., 2006, Vol. 2, pg 438-446) in view of Zhou (Steroids, 2005, Vol. 70, No. 5-7, pg 407-417), Hillmann (Cancer Res. 2000, Vol. 60, No. 7, pg 2056-2062) and Rhen (N. Engl. J. Med., 2005, Vol. 353, No. 16, pg 1711- 1723) and optionally 6140081, 6453242, 6534261, WO 98/53058; WO 98/53059, WO 98/53060; WO 02/016536, and WO 03/016496, 5789538, 5925523, 6007988, 6013453, 6200759, WO 95/19431, WO 96/06166, WO 98/53057, WO 98/54311,WO 00/27878, WO 01/60970, WO 01/88197, WO 02/099084, 6785613; WO 98/53057; WO 01/53480, 2003/0092000, 5789538, 6013453, 6410248, 6733970, 6746838, 6785613, 6866997, 7030215, WO 01/088197, WO 02/099084, 2003/0044957, 2003/0108880, 2003/0134318, 2004/0128717, WO 96/06166 and 6784136, Urnov (Nature, 2005, Vol. 435, pg 646-651) and 2005/0064474, as applied to claims 1-3 and 6-10 above, and further in view of Miller (7914796).

For those keeping score at home, those are rejections citing 58 reference references and 48 references, respectively.

### Can it really be obvious to combine so many references?

When confronted with so many references it is tempting to argue that the need to rely on so many references is itself evidence of non-obviousness. It’s so tempting, in fact, that the MPEP has a form paragraph specifically for responding to this argument:

¶ 7.37.06 Unpersuasive Argument: Number of References

In response to applicant’s argument that the examiner has combined an excessive number of references, reliance on a large number of references in a rejection does not, without more, weigh against the obviousness of the claimed invention. SeeIn re Gorman, 933 F.2d 982, 18 USPQ2d 1885 (Fed. Cir. 1991).

In other words, this argument and $1300.50 will buy you a cup of coffee and an RCE. The Examining corps is not concerned with the impracticality of dealing with so many references. (Such practicalities do generally limit the number of references relied on in AIA trials and district court proceedings, as discussed in two excellent posts on ptablaw.com and PatentlyO.)

### Responding to obviousness rejections with huge numbers of cited references.

So how can you possibly respond to such a rejection given limited time and budget? Luckily (at least in my personal experience), such laundry lists of alternative references are usually used for claim limitations which are not really at the core of the invention. Rather, they are used for limitations that simply provide context/antecedent basis/etc. The “core” limitations usually only have one or two references cited against them. In those cases, all you need to do is show that those one or two references do not in fact teach the claim elements they are alleged to teach (which, BTW, is not “attacking references individually” when done properly, as discussed in this Mr. IPLaw post). Because many of the references do not need to actually be addressed, rejections that are extreme outliers with huge numbers of references are probably not that big of a deal. What is much more burdensome is when multiple references are relied on for the “core” limitations.

### “Burdensome” Rejections and Allowance Rates

Using this assumption that some intermediate number of cited references represents the most-burdensome rejections, I looked at the relationship between “burdensome” rejections and allowance rate. Specifically, I looked at the correlation between allowance rate and the percentage of applications having a “burdensome” rejection for both art units and individual examiners. I defined a “burdensome” rejection as one citing between 5 and 10 references. These upper and lower bounds were (somewhat arbitrarily) selected based on: (1) the distribution of obviousness rejections (first chart below); (2) the data in the ptablaw.com blog post mentioned above; and (3) my own experience.

### Distribution of Obviousness Rejections By Number of References in a Single Rejection

The first chart below shows the distribution of obviousness rejections by number of cited references broken down by technology center.

As you can see, applications having a “burdensome” rejection of between 5 and 10 references represents a small fraction of applications. (Note: the data for this chart and subsequent charts in this post comes from the same USPTO Office Actions Data set that was discussed here, here, and here)

### More Cited References Correlate with a Lower Art Unit Allowance Rate

The chart below shows the percentage of an art unit’s applications which received a burdensome rejection. Overlaid with this is the art unit’s allowance rate. The art units are ordered from highest percentage of applications with a burdensome rejection on the left to lowest percentage of applications with a burdensome rejection on the right.

Although the allowance rate line is pretty noisy, there is a distinct upward trend in the allowance rate as the percentage of applications with burdensome rejections declines. The correlation coefficient is approximately -0.5, which would generally be considered a moderate correlation.

### More Cited References Correlate with a Lower Examiner Allowance Rate

The chart below shows the percentage of an examiner’s applications which received a burdensome rejection. Overlaid with this is the examiner’s allowance rate. The examiners are ordered from highest percentage of applications with a burdensome rejection on the left to lowest percentage of applications with a burdensome rejection on the right.

Again the allowance rate line is pretty noisy, but again there is a distinct upward trend with a correlation coefficient of approximately -0.5.

### Outliers

A final, random factoid is that both the Examiner data and Art Unit data have one pretty clear outlier:

- 71% of Applications in the data set for Jean Paul Cass have a rejection citing between 5 and 10 references. Second place is a relatively distant 66% (a tie between Viren Thakur and Martin Rogers).
- 42% of applications in the data set for art unit 1718 (“Coating, Etching, Cleaning, Single Crystal Growth”) have a rejection citing between 5 and 10 references. Second place is 33% (1613 – “Organic Compounds: Bio-affecting, Body Treating, Drug Delivery, Steroids, Herbicides, Pesticides, Cosmetics, and Drugs”).