New York Codes, Rules and Regulations
Title 2 - DEPARTMENT OF AUDIT AND CONTROL
Chapter VI - New York State and Local Employees' Retirement System and New York State and Local Police and Fire Retirement System
Part 343 - Service Crediting For Teachers, Tiers Two, Three And Four
Section 343.2 - Definition of school year

Teachers shall be considered to have been employed for an entire school year for service crediting purposes if and only if they have been reported by the employer to the Retirement System as being paid on the payroll for not less than 200 days (including paid vacation and paid holidays) between September 1st of any calendar year and August 31st of the following calendar year.