Before a patent is granted, it undergoes a rigorous examination process to determine whether the invention is novel and non-obvious in light of prior art. Forward, backward and Self citations are three important types of citations that are used in this process.

Backward Patent Citations:

A backward citation is a patent or non-patent reference to a subject patent that has been cited:

  • During the prosecution of the subject patent by the patent examiner; or
  • During the opposition by any third party; or
  • In the invention disclosure statement; or
  • Search report generated by any of the National or Regional Patent Office; or
  • International Search Report (ISR) and International preliminary report on patentability (IPRP)
  • The purpose of a backward citation is to identify prior art that is relevant to the invention being claimed in the subject patent application.

Backward citations are critical because they help examiners determine the novelty and non-obviousness of an invention in light of prior art and essentially identifies potential barriers to the grant of the subject patent.

Furthermore, backward citations (P1, P2, P3 and P4) can also be used to assess the validity of a granted patent. If a patent is challenged in court, the patent owner can use backward citations to demonstrate that the invention is novel and non-obvious in light of the prior art. Conversely, the challenger can use backward citations to show that the invention is not new or non-obvious.


Forward Citations:

A forward citation is a reference to the subject patent or a non-patent document that has been cited by the inventor in their own patent application. The purpose of mentioning subject patent in the document of forward patent citations (PA and PD) is to identify the technical gap for establishing the novelty and non-obviousness of the invention being claimed in the patent applications (PA and PD). By citing the subject patent as a prior art, the inventor is demonstrating that there exists technical gap in the closest known prior art which the inventor has solved by providing an inventive and useful solution.

Forward citations are important as they help patent examiners determine the scope of the invention being claimed.

Furthermore, forward citations can also be used to assess the value of a patent. The more forward citations a patent application receives, the more valuable it is considered to be. This is because a high number of forward citations indicates that the invention is technologically strong and has wide range of useful applications.

Patent Self-Citations

For the subject patent application, self-citations are the patent references to the subject patent cited:

  • as a patent family for which subject patent application is filed as non-provisional or continuation in part or divisional application claiming priority from one of the self-cited patents (Po , P", P' and P*); or
  • which are filed by the same inventor or assignee.

One of the advantages of having high number of self-citations is that the company has done in-depth research in that particular technology domain and self-sufficient and might not need to buy or license much from others in order to build their product.


Forward, backward and self-citations are important tools in patent prosecution, valuation and litigation. They help establish the novelty and non-obviousness of an invention and assess its potential value in the market. There are many patent metrics that can be evaluated based on the number of citations for assessing the strength of a patent portfolio.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.