1. Short title This Act may be cited as the Family First Transition Assistance Act of 2019 . 2. Finding The Congress finds that the Department of Health and Human Services has full authority to execute section 50711 of Public Law 115–123 , giving certainty to States and expediting help to children and families. 3. Phase-in of 50 percent well-supported prevention practices requirement Section 474(a)(6)(A)(ii) of the Social Security Act ( 42 U.S.C. 674(a)(6)(A)(ii) ) is amended to read as follows: (ii) (I) not less than the applicable percentage of the total amount expended by a State under clause (I) for a fiscal year shall be for the provision of services or programs specified in subparagraph (A) or (B) of section 471(e)(1) that are provided in accordance with well-supported practices; and (II) for purposes of subclause (I), the term applicable percentage means— (aa) 0 percent, in the case of each of fiscal years 2020 through 2023; (bb) 20 percent, in the case of fiscal years 2024 and 2025; (cc) 35 percent, in the case of fiscal years 2026 and 2027; and (dd) 50 percent, in the case of fiscal year 2028 and each succeeding fiscal year