Patent Application Drafting – The Written Description and Enablement Requirements

The requirement “Written Description” sounds simple, but when it comes to describing an invention in order to obtain a patent, it can be a tricky element to fulfill.

In fact, many inventors fail to appreciate the significance of the Written Description requirement, as well as that of Enablement, when applying for patent protection.

To appreciate the importance of these requirements it is important to remember that a granted patent is essentially a limited monopoly awarded to the inventor by the government. In exchange for that monopoly, the government wants some assurance that once the patent expires the invention will be available to the public.  So the requirements for Written Description and Enablement are designed to put “the public in possession of the invention and to enable those skilled in the art to make and use the invention.”[1]

Written Description

On its face, the Written Description requirement sounds pretty easy to fulfill – just describe what you have invented in a way that discloses the technologic knowledge underlying the invention and shows that the applicant had possession of the invention.  But the Written Description requirement can actually be a bit tricky to fulfill.

Specifically, the courts have stated that the Written Description requirement, “implements the principle that a patent must describe the technology that is sought to be patented; the requirement serves both to satisfy the inventor’s obligation to disclose the technologic knowledge upon which the patent is based, and to demonstrate that the patentee was in possession of the invention this is claimed.” [2]

For example, let’s say that the invention is a chair with four legs, a seat, a back and two arms.  The inventor has crafted the chair out of wood, but realizes that metal would work as well.  He is also thinking that the chair would be more comfortable if the seat and the back were padded.  So he writes the application stating that the chair can be made out of wood or metal, that the various parts are held together with glue, nails or screws, and that the seat can optionally be padded.

During examination of the application, the inventor wants to introduce a claim to a chair made of plastic and another claim directed to a chair with a padded back.  But there is a problem:  he did not describe plastic as a suitable material or a padded back as an option. There is no Written Description for a plastic chair or a chair with a padded back.  Consequently, the inventor cannot claim what he did not disclose to the public or have in his “possession” at the time the application was filed.

So does it make sense to simply think of all of the possible materials and/or combinations that could be present in an invention and describe those?  Not necessarily.

Most patent applications are published before examination begins.  Once the application is published, in some circumstances that publication can be used to reject the same inventor’s future inventions/patent applications.  As a result, one must be careful to say enough so that any changes to the claims have written description support, but not too much so that patent applications directed to the second and/or third generations of the claimed product are rejected for novelty or non-obviousness over the initial patent application. Because you need to walk such a fine line between what you should and should not say, you need to be well-versed in the law to ensure the description is written in a way that best protects your interest.


The Enablement requirement adds another layer of complexity.

The purpose of the Enablement requirement is to ensure that a description of the invention is communicated in the body of the application (aka the “specification”) in such a way so that someone working in the same area of technology would know how to make and use the invention.

While this sounds very similar to the Written Description requirement, the two are separate and distinct. The purpose of the Written Description requirement is broader than to merely explain how to “make and use.”

For example, considering the chair invention discussed above, while a claim directed to a chair with a padded back would be rejected for lack of Written Description, it would likely be considered enabled/meeting the Enablement requirement.  That is because just stating in the claim that the back could be padded would probably be enough so that another chair maker would know how to make and use a chair with a padded back.

How can one analyze whether a patent application is enabled?  Is it necessary to describe every little detail in order to fulfill the Enablement requirement? No, a patent application does not need to teach or describe – and preferably omits – what is well known in the area of technology involving the invention. Instead, the Supreme Court has stated that the proper question to ask is “Is the experimentation needed to practice the invention undue or unreasonable?”[4]

The fact that experimentation may be complex does not necessarily make that experimentation undue as long as that type of complex experimentation is typically engaged in by the area of technology associated with the invention.  In other words, the fact that some experimentation is necessary in order to make or use the invention is not the critical factor, but whether that experimentation is undue.[5]

When determining whether experimentation is undue, one considers the level of predictability in that area of technology, the level of skill of ordinary practitioners in that technology and what is already known in the literature associated with the invention’s technology, among other things.

Using the chair example to illustrate, the inventor described that parts of the chair could be held together with glue, but did not indicate what types of glue.  So would a claim to the chair being assembled with glue be enabled?  Probably yes because while there are many different types of glue, a chair maker would be aware of the types of glue generally used for assembling furniture and the amount of experimentation that would be required before finding a glue that would work would not be undue or unreasonable.


The over-simplified examples used above illustrate the Written Description and Enablement requirements, but the analysis for actual inventions is far more complex.  Clearly, drafting a patent application that will provide enough disclosure to satisfy the Written Description and Enablement requirements – but not too much so that future applications are adversely affected – is an intensive and challenging task that requires significant knowledge and understanding of the rules and court decisions interpreting those rules.  Consequently, most inventors find that collaborating with a patent attorney provides the best insurance for being able to move through the patenting process to granted patent in the most efficient manner.

Susan Gorman, Ph.D., Esq., is principal of Gorman IP Law, a law firm focused on helping companies leverage intellectual property assets to maintain a competitive advantage, enhance market share, plan for growth and better manage resources and expenses. Through a proprietary process, Gorman IP Law helps businesses build a formal IP strategic plan that defines your business goals, establishes benchmarks and allows you to better project costs. Dr. Gorman can be reached at

The information contained herein has been prepared by Gorman IP Law, APC, for informational purposes only and is not legal advice.

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[1]  Manual for Patent Examination and Procedure (MPEP) § 2162

[2] Capon v Eshhar, 76 USPQ2d 1078, 1084 (Fed Cir. 2005)

[3] MPEP 2161.01

[4] Mineral Separation v Hyde, 242 U.S. 261, 270 (1916)

[5] In re Angstadt, 190 USPQ 214, 219 (DDPA 1976)