One of the most important attributes of a patent is its term or duration of enforceability. In 1995, the US patent system began calculating patent term based on the priority filing date of an application rather than a patent's issue date. Under the prior rule, a patent would remain in force for 17 years from the date of issue. Under the “new” system, the term is 20–years from the priority filing date. The three extra years were intended to account for a typical prosecution delay of three years. In addition, Congress added a patent-term-adjustment (PTA) provision to lengthen the patent term in instances where the USPTO unduly delayed in issuing a patent.
Study: For this study, I wanted to consider how the change has actually impacted patent term. To do this, I created a database of 50,000 recently issued patents and calculated the term under both the old and new system. For the calculation under the new system, I added 20–years to the earliest priority date (excluding provisional and original foreign filing dates) and then added any patent-term-adjustment. To calculate the term under the old system, I added 17–years to the issue date unless the patent had a family member (e.g., continuation application) with an earlier issue date. In that case, I added 17–years to the issue date of the family member based on an assumption that a terminal disclaimer would have been filed in the case. Because of some potential data discrepancies, I excluded the extreme 1% of results and also patents on applications filed proir to the 1995 change-over.
Results: Most patents (64%) have a longer term under the new system than they would have been entitled under the older system. Under the new system, the median patent has a term of about 8–months longer than if the term had been calculated under the old system. For 43% of the patent, the terms are are within 1–year of what would have been calculated in the old system; and 89% are within 2–years. Of course, there are some extremes. As you might imagine, patents that benefit most under the new system are those that have the greatest patent term adjustment (PTA). Patents in TC 1600 (Biochemistry and Organic Chemistry) comparatively fared the worst. Those patents on average lose 11–months of patent term in the new system as compared to the old system.