What is the significance of the filing date for foreign applications in priority claims?

The filing date of foreign applications is significant in priority claims for the following reasons:

1. It establishes the effective date of the priority claim.
2. The date accorded is the date on which the specification and drawing were filed, not necessarily the date of the petition (which is called the application in some countries).
3. This date is used to determine the applicability of prior art and the eligibility for certain patent term adjustments.

The MPEP states: “In some instances, the specification and drawing of the foreign application may have been filed at a date subsequent to the filing of the petition in the foreign country. Even though the petition is called the application and the filing date of this petition is the filing date of the application in a particular country, the date accorded here is the date on which the specification and drawing were filed.” (MPEP 216)