You will find in a multi-TA setting that there are numerous issues which can arise in terms of grading. The following statement, provided by the UC Davis website, describes these issues well.
“Courses with more than one TA require special attention by the instructor. There are several areas which merit such attention. The general principle is that of equity, which has several practical applications:
"Uniformity of grading, in fairness to students: It is the responsibility of the instructor to ensure uniformity of grading. If more than one TA is to grade a particular assignment, the graders and instructor should meet to establish uniform criteria for grading. They should also meet before work is returned, in order to determine that the criteria are met. Instructors should also recognize their responsibility to adjudicate problems arising from apparent failure to achieve uniform grading.”
