How to use the Patent Forward Citations in AcclaimIP

Forward Citations

The "Forward Cites" column (Forward Citations Column) in the search result grid displays the number of forward citations earned by each patent.  The column can be exposed by default by editing your preferences, or it can be displayed ad-hock by checking it in the Columns menu in the column headers.

Forward citations are updated weekly, and the column is available to all user plans.  It is sortable, searchable and facetable.

patent-forward-citations

What are Forward Citations

Both the applicant and the patent examiner must find and cite documents that may anticipate the claimed invention, or might be similar to the claimed invention and limit the scope of the patent protection, or which generally reveal the state of the art of the technology.  These are called reverse citations.  From the perspective of the patents being cited, they are forward citations.  Therefore, the number of forward citations a patent receives is often used as a measure of a patent's significance.

Here are a few things to remember about forward citations:

Documents that cite a patent are usually at least 12 months newer than the cited patent due to a lag in publishing of filed applications.  As a result, patents that are filed about the same time as another similar patent will rarely cite each other.

Patent applications that receive a large amount of forward citations are generally cited by the same applicant.

New patents rarely earn many forward citations because it takes time for a patent to be recognized and cited by newer patent documents.  In other words, forward citations build over time and a strict citation analysis will favor older patents.

How Patent Forward Citations are Calculated

Forward citations are derived from other documents' reverse citations.  Every week, AcclaimIP processes thousands of new patents, and each new patent cites (reverse) from zero to thousands of older patents.  

To illustrate, from January to Ocotober 2012, the median number of reverse citations was seventeen. However, there are over 500 patents that cite at least 1000 other patents, and about 1000 patents that do not cite any other patents. The trend, however, is that the number of reverse citations (therefore the number of forward citations per patent) has been increasing for the past 20 years.  Compare 2012 to twenty years ago.  In 1992, the median number of reversed citations per patent was only 9–about half as many as today!

New patents are available in AcclaimIP the day they are issued, however, forward citations are indexed on the weekends.  As a result, on Monday all forward citations are up to date.

How Patent Forward Citations are Used

Compared to other value indicators in patent data, forward citations are perhaps the most studied and the most "accepted" measure of a patent's value or significance.  The notion is that if a patent is cited often by other patents, then other entities are more likely to be building on the patented technology, and the highly cited patents are more likely to be fundamental or important in some way.  

Correlating the number of forward citations to value is controversial primarily because searchers don't use them correctly, not because there is a problem with forward citations in themselves.  You simply cannot say that one patent is more valuable or important than another because it has more forward citations!

To draw an analogy, it is an undisputable fact that teenage drivers get in more accidents than drivers in their 30s, but can you say that Zach, the teenager is a worse driver than Jason, the 35-year-old?  No way, because a driver's age in not a measure on one's driving skills–but rather a value that correlates to a person's driving skill.  Simililary, we can say, highly cited patents as a group are more valuable/important/fundamental than patents that are not cited, but we can make no judgement on an individual patent.

In my experience, forward citations are a good measure of value only in the sense that forward citations can point to important, or fundamental patents.  No professional patent searcher relies on forward citation metrics to determine a patent's quality.  However, they do use forward citations as a guide by focusing their attention on patents that are more likely be be significant.

If you do a search, then sort the results by forward citations, more often than not, you'll find many of the better patents on the top of the list.

Advanced Syntax:

To query the forward citation column, use the ANA_INREF_CT (think inbound references) field code.  As with other numeric fields, it is often useful to use a range query.

ANA_INREF_CT:0  –>  Finds patents that are un-cited

ANA_INREF_CT:[10 to *]  –>  Finds patents that have 10 or more forward citations.

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