Different requirements exist for each type of F-1 employment, but there is one basic requirement that must be met for any F-1 employment: You must be enrolled in a full course of study.
Once employment is authorized you must maintain eligibility or you will lose your right to continue employment, even if it was authorized in writing.
Yale students in F-1 status may work "on campus" up to 20 hours per week when school is in session and full-time during holiday and vacation periods. A new F-1 student who has been issued a form I-20 may work prior to the commencement of classes, but for no more than 30 days prior to the actual start date of classes.
USCIS defines on-campus employment as the following:
Type 1: Employment at Yale University: Any on-campus work for which you receive a paycheck (or other compensation, such as room and board, etc.) from Yale University or the Yale-New Haven Hospital.
Type 2: On Campus Work affiliated with an On-Site Commercial Firm on Yale's Premises. This includes work on Yale's campus for a commercial firm if and only if this work provides direct services to Yale students.
Type 3: Certain Off-Campus Employment where there is an official educational relationship between Yale and the off-campus employer. USCIS regulations allow work at an off-campus location provided the:
location is educationally affiliated with Yale,
educational affiliation is associated with your school's established curriculum or is related to a graduate level research project which your school has contracted to perform, and
work is an integral or important part of your program of study.
With permission of the J-1 program sponsor, students in J-1 status may work up to 20 hours a week when classes are in session and full time during the break periods. (Please check with your school for other requirements about work during the academic year.) If Yale University is your J-1 program sponsor you must seek permission to work from OISS before commencing work.