Which of the following methods can be used to correct inventorship in an issued patent?

The correct method to address the correction of inventorship in an issued patent is through a Certificate of Correction. This process is specifically designed to amend minor errors in a patent, including those related to inventorship.

When inventorship needs to be corrected, this typically involves situations where the names of the inventors were incorrectly listed due to clerical errors or oversight. In such cases, a Certificate of Correction can be filed with the United States Patent and Trademark Office (USPTO) to officially amend the patent document to reflect the accurate inventors.

Filing a letter to the USPTO is not a formal method recognized for correcting inventorship, as the USPTO requires specific forms and acknowledged procedures such as the Certificate of Correction to effectuate changes in patent documents.

While filing a new application might address issues of inventorship, it would create a new patent and not correct the existing patent, making it an impractical solution specifically for corrections. An oral argument before a board would not be applicable in this context, as it pertains more to appeals or hearings rather than to administrative corrections of patent documents.

In summary, the Certificate of Correction is the proper avenue for correcting inventorship in an issued patent, as it follows the established legal framework and procedural requirements set