How does a preliminary examination report help in the PCT and patenting process?

What are the consequences and advantages of international preliminary examination?

Is it worth it in terms of time and money invested?

The preliminary examination criteria includes novelty, inventiveness and whether the invention is industrially applicable. Even though it is not binding, a favorable report will assist the prosecution of national patent applications which will generally proceed rapidly to the grant of a patent where the IPRP is favourable.

However I still don´t really appreciate the difference with the International Search Report (ISR) as this report includes also the written opinion of the International Search Authority (ISA) on the same issues (novelty, inventiveness and industrial applicability).

2 Answers 2


It is used primarily in the case of amendments made after the ISR. If you received a negative ISR and therefore decide to amend claims to increase the chances of patentablity, then going in to Chapter II and getting a positive IPRP can help when you take the amended claims into the regional or national stage.


PCT is an international process. The first search report you receive in a PCT process is an ISR.

If the ISR is favorable (positive or only mentioning small clarity issues), you could just enter into the national/regional phase.

If the ISR is not favorable, one of the possibilities to improve your chances is to request an international preliminary examination.

The benefit of requesting an international preliminary examination is that you get a chance to argue for or amend your application while you are still in the international phase. And you could argue for or amend your application till you run out of time. (For most countries the application enters into the national/regional phases after 30 month from priority date.) As soon as your application enters into the national/regional phases, you have to deal with each country/region separately.

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