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The Reciprocity of Search

65 Pages Posted: 1 Dec 2011 Last revised: 2 Jan 2015

Tun-Jen Chiang

George Mason University School of Law

Date Written: November 30, 2011


When discussing search in patent law, everyone considers the problem in terms of producers looking for patentees. But search is reciprocal. In designing a patent system, we can have producers look for patentees, or patentees look for producers. Either will result in the ex ante negotiation that is the goal of a property system. The legal rule that produces the most efficient social outcome depends on identifying the party with the lower search cost.

The corollary is that patentees should have the duty of search when they are the lower cost searcher. For example, if there are thousands of patents covering a product, but only one producer in the industry, then it is likely to be more efficient to have patentees find the well-known producer to initiate licensing negotiations, rather than have the producer search for each of thousands of unknown patentees. The Article provides some suggestions on how patent law can utilize the reciprocity insight to efficiently reduce inadvertent infringement and encourage legitimate commercialization.

Keywords: Coase theorem, reciprocity of causation, cost allocation, least cost avoider, patent search, information cost, patent thicket, contributory negligence

JEL Classification: K11, O34

Suggested Citation

Chiang, Tun-Jen, The Reciprocity of Search (November 30, 2011). Vanderbilt Law Review, Vol. 66, No. 1, January 2013, pp. 1-64; George Mason Law & Economics Research Paper No. 11-52. Available at SSRN: or

Tun-Jen Chiang (Contact Author)

George Mason University School of Law ( email )

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