The international search report enables you to determine the chances of obtaining patents in the PCT contracting states. It consists of a list of patent documents and technical literature. Also, the International Search Authority (ISA) is responsible for providing this report. The ISR result can be both in your or against your favor. Depending on your application quality, you may or may not come across closely overlapping prior art. This however will help you in deciding whether and how you should proceed further with your application (this is when search report is favorable) or how you can amend the claims in your application or can withdraw them (in case of unfavourable international search report). Thus, the ISR carries a lot of weight and an applicant must ensure that they go through it as thoroughly as possible.
Also, do make sure that you check out this free e-book: A Quick Guide to Patents.
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