New York Codes, Rules and Regulations
Title 2 - DEPARTMENT OF AUDIT AND CONTROL
Chapter V - Public Authorities
Part 203 - Budget And Financial Plan Format, Supporting Documentation And Monitoring-public Authorities
Section 203.7 - Supporting documentation

The public authority shall prepare working papers that detail the assumptions and methods of estimation used to calculate all operating and capital budget projections, consistent with prudent budgetary practices. The working papers shall be completed contemporaneously with the release of the budget or plan and shall include a statement supporting the reasonableness of each estimate, and the underlying information on which the estimate is based, such as actual results from prior years, inflationary trends and economic data, assumptions regarding the cost of future collective bargaining agreements, utilization, demographic and other pertinent data.