The value of a granted patent is inherently linked to the value of the underlying technology. However, patent value is also impacted by the skills of the patent drafter in producing a document that will stand up to the rigours of the patent examination process in possibly numerous jurisdictions, and deliver useful results to the applicant. An important goal of the drafter is to ensure that the inherent value is not compromised and that steps are taken to maximise desirable outcomes.

Most patent applications are drafted with some knowledge of the prior art, but typically not all potentially relevant prior art is known, and even if searching is undertaken as part of a pre-drafting exercise, patent examiners have a knack of uncovering new prior art of which the drafter was unaware.

What steps can the applicant and drafter take to maximise desirable outcomes, yet, at the same time, work within a reasonable cost window?

International patent application process

A common route to seeking patent protection is to make use of an International Patent Application filed through the Patent Cooperation Treaty (PCT). Such an application affords the applicant the future right to file national patent applications in jurisdictions of choice; currently 152 jurisdictions are signatories to the PCT.

Benefits of the PCT

As well as delaying jurisdictional choice, the PCT process results in a prior art search (International Search Report) and written opinion on patentability (International Search Opinion). The search and opinion, although not binding on national patent offices, provides a useful indicator of things to come.

It’s in the claims!

In assessing patentability, it is the claims of the patent application that are examined. If features of the technology outlined in the description are not present in the claims then they will not be examined. Therefore, it is in the applicant’s best interest that all relevant features be included in the claims so that the benefit of the International Search Opinion is potentially maximised.

So how many claims are allowed?

The PCT regulations state: “The number of the claims shall be reasonable in consideration of the nature of the invention claimed”. Relevantly, there is no numerical limit on the number of claims and no extra fees are payable on the basis of claim number (although extra fees are payable for pages in excess of 30). This assumes that all the claims are directed to a single inventive concept so as to avoid an objection for ‘lack of unity’.

Why is this significant?

Including a relatively large number of claims creates the opportunity to have many more features examined, and at no extra cost. However, it is surprising that many international applications are only filed with a relatively small claim set of between 15 and 25 claims.

This may be due to drafters already ‘tailoring’ the number of claims with an eye on future nationalisation, where numerous jurisdictions impose onerous excess claims fees on filing. However, this should not represent a barrier to including a large number of claims in the international application, as claims numbers can be paired back for national filings, thus avoiding excess claim fees in the majority of jurisdictions.

Multiple dependencies

Another significant strategy at the international application stage is to include multiple dependencies in the claims. This affords the opportunity to claim features of the invention both in a related and non-related fashion. While it is possible (and where possible, desirable) to include such relationships in the description of the patent application it can often be extremely time consuming, and therefore costly, to draft a description covering all possible combinations of features. The exercise is facilitated, through a reduction in time, and thus cost, by including these combinations in a well drafted set of multiply dependent claims. On nationalisation, the multiple dependencies may be removed for those jurisdictions which do not permit them or place limitations on their use, for example, the United States.

New matter

After a PCT application is filed it is very difficult to add new material to the application. In some jurisdictions, notably Europe and China, it may be impossible to construct claims which are based on certain combinations of features, unless the combination is explicitly disclosed in the application as filed (i.e., the PCT application). Having a relatively large claim set which includes multiple dependencies can improve the chances of tailoring claims to contain specific combinations of features, as these feature combinations, are, arguably, already explicitly disclosed through dependent claim relationships. This can prove invaluable, should prior art be cited during national examination which cuts across the broader claims of the application, forcing the applicant to restrict to narrower feature combinations.


The PCT process can be a valuable tool in ascertaining the patentability of an invention and its value may be increased though the drafter’s attention to producing a claim set for examination that maximises learning. This can be achieved through use of a relatively large set of claims which includes multiple dependencies. Such claims can also provide the basis for future claim amendments which might otherwise be unallowable, if reliance is based solely on the disclosure in the description of the patent application.