increase, or the determination of whether the taxpayer is described in section 24(i)(2)(C)(ii)(II). . (d) Effective date (1) In general Except as provided in paragraph (2), the amendments made by this section shall apply to taxable years beginning after December 31, 2019. (2) Special rule for election to claim credit on prior year return In the case of a taxpayer who makes an election under section 24(i)(3) (as added by subsection (a)) with respect to a child born before January 1, 2021 (determined without regard to such section), the amendments made by this section shall apply to taxable years beginning after December 31, 2018. (e) GAO Study (1) In general Not later than 2 years after the date of enactment of this Act, the Comptroller General of the United States shall submit to Congress a report on taxpayers making an election under section 24(i) of the Internal Revenue Code of 1986, as added by subsection (a). (2) Matters included The report submitted under paragraph (1) shall include the following: (A) The total number of taxpayers making such election for each month during 2019, and the average number of days occurring during the period beginning on the date on which such election is made and ending on the date on which the Secretary of the Treasury (or the Secretary's designee) makes a determination that an increase under such section is allowed. (B) The total number of taxpayers receiving an increased credit under such section during 2019, and the average number of days occurring during the period beginning on the date on which such election is made and ending on the date on which any refund related to such increase is paid. (C) An identification of any excessive delay in any of the periods described in subparagraphs (A) and (B), and a description of the causes for such delay, with recommendations to address those excessive delays. (D) The total number of taxpayers making such election who failed to submit a social security number of the qualifying child or such other information required pursuant to