### Question
Can you define what base period costs means?


### Answer
**Base period costs** is defined as the following in *APPENDIX U.S.C. § 1173*:

> the average of the subsidizable wage cost of United States officers and crews for the preceding annual period ending June 30 (calculated without regard to the limitation of the last sentence of paragraph (D) of this subdivision but increased or decreased by the increase or decrease in the index described in subdivision (3) of this subsection from January 1 of such annual period to January 1 of the base period), and the collective-bargaining costs as of January 1 of the base period: *Provided*, That in no event shall the base period cost be such that the difference between the base period cost and the collective-bargaining costs as of January 1 of any base period subsequent to the first base period exceeds five-fourths of 1 per centum of the collective-bargaining costs as of such January 1 multiplied by the number of years that have elapsed since the most recent base period

#### Citation:
  - *APPENDIX U.S.C. § 1173*
  - Heading: **CHAPTER 24A-MERCHANT MARINE ACT, 1928 > SUBCHAPTER VI-VESSEL OPERATING ASSISTANCE PROGRAMS > Part A-Operating-Differential Subsidy Program**

