Do Restriction Requirements Vary by Technology Center?

I have been preparing and processing patent applications for about fourteen years, primarily within the electrical, mechanical and software technologies.  From my perspective, the issuance of restriction requirements seems to be somewhat random and inconsistent.  It is often the case, in fact, that I do not get a restriction requirement when there might be a relatively good reason for one to be issued.

On the other hand, I have always heard that practitioners in the chemical and biotechnological arts suffer from a higher than average issuance of restriction requirements.  I set this week to do a little research to see whether this assumption could be statistically validated using PatentAdvisor Search Tool.

Restriction requirements are governed by MPEP § 806.06 .  In a nutshell, a restriction requirement is to be issued by an examiner where there are multiple distinctly claimed inventions in one patent application and it would be overly burdensome for the examiner to go forward with one application.  For patent prosecutors and their clients, restriction requirements represent a significant cost increase as splitting one patent application into several new applications results in the multiplication of fees and, often, loss of protection due to expense limitations.  The pros and cons probably do depend on the technological context, however.

[Varsity-1]

Claims presented in the chemical and biotechnological arts, as I understand it, are seen as prime targets for restriction requirements because they often include different species within a genus.  MPEP 1.142 does allow for a patent application to link a reasonable number of species to a generic claim. However, many patent prosecutors claim that patent examiners in the chemical and biotechnological arts are very eager to split up this type of claim set.

However, when we review the facts (derived from the PatentAdvisor database); they tell a different story.  The database contains statistics and analysis, including the frequency of restriction requirement issuance, for all art units in the patent office.  Following is a table that shows the commonality of restriction requirements across all art units in four of the major patent office technology centers:

Tech. Center	RRs issued	Patents issued	Average %	MaxArtUnit %	MinArt Unit %
Biotechnology	145,620	264,970	58.98	89.09	2.49
Chemical	73,375	285,963	28.21	48.50	13.36
Semiconductors	115,535	567,861	22.51	60.29	5.15
Mechanical Engineering	78,308	378,109	22.10	49.59	3.80

This table validates the perception that the biotechnology technology center average issuance of restriction requirements is high.  Interestingly, this tech center also has the art unit with the lowest occurrence of restriction requirements across all art units regardless of tech center.  It is worth noting; however, the art unit in question (Art Unit 1661) is dedicated to plants.

Surprisingly, although the chemical tech center does have a higher average issuance of restriction requirements issued than semiconductor patent applications or mechanical engineering applications, the difference is quite small.  Finally, it is worth noting that the Semiconductors Technology Center includes art units with a higher rate of restriction requirements than any art unit in the Chemical Technology Center (2811 at 60% and 2814 at 50%).

Knowing the frequency of restriction requirements in an art unit before drafting an application can prepare both the prosecutor and the client for potential restriction requirements.  Additionally, knowing the likelihood of restriction requirements in a specific art unit before filing could help suggest alternate strategies, such as postponing disclosure of some species for a divisional application, extending the patent term and potentially avoiding a restriction requirements