; and (2) an identification of the critical assumptions and the source of data underlying that estimate. (c) Distributional effects Any estimate referred to in subsection (a) shall, to the extent practicable, include the distributional effects across income categories resulting from major legislation. (d) Definitions In this section: (1) Major legislation The term major legislation means a bill, joint resolution, conference report, amendment, amendment between the Houses, or treaty considered in the Senate— (A) for which an estimate is required to be prepared pursuant to section 402 of the Congressional Budget Act of 1974 ( 2 U.S.C. 653 ) and that causes a gross budgetary effect (before incorporating macroeconomic effects and not including timing shifts) in a fiscal year in the period of years of the most recently agreed to concurrent resolution on the budget equal to or greater than— (i) 0.25 percent of the current projected gross domestic product of the United States for that fiscal year; or (ii) for a treaty, equal to or greater than $15,000,000,000 for that fiscal year; or (B) designated as such by— (i) the Chairman of the Committee on the Budget of the Senate for all direct spending and revenue legislation; or (ii) the Senator who is Chairman or Vice Chairman of the Joint Committee on Taxation for revenue legislation. (2) Budgetary effects The term budgetary effects means changes in revenues, direct spending outlays, and deficits. (3) Timing shifts The term timing shifts means— (A) provisions that cause a delay of the date on which outlays flowing from direct spending would otherwise occur from one fiscal year to the next fiscal year