; (XVIII) in any State in which the State regulatory authority has designated 1 or more entities to administer electric ratepayer-funded efficiency programs approved by the State regulatory authority, provide that electricity savings and natural gas savings achieved through those programs shall be distributed proportionally among retail electricity suppliers and retail natural gas suppliers; (XIX) include guidance for retail electricity suppliers and retail natural gas suppliers to calculate and document business-as-usual consumption projections; (XX) include guidance for estimating savings using information from the database established under paragraph (3) based on similar measures and programs in other settings with appropriate adjustments, as necessary; and (XXI) incorporate advances in the science of policy evaluation, such as the use of— (aa) randomized control trials; (bb) other experimental and quasi-experimental approaches; and (cc) large data sets and machine learning techniques; and (ii) procedures and standards for third-party verification of reported electricity savings or natural gas savings. (2) National Academy of Sciences study Not later than 180 days after the date of enactment of this section, the Secretary shall offer to enter into an agreement with the National Academy of Sciences, under which the Academy shall— (A) evaluate existing state-of-the-art methods for evaluating energy efficiency policies and measures; (B) identify approaches in program evaluation literature that may be brought into the energy efficiency domain, including— (i) randomized control trials and other experimental or quasi-experimental approaches; (ii) control of confounding factors; (iii) longitudinal studies; (iv) assessments by neutral arbiters; and (v) disclosure of data for replication; and (C) not later than 18 months after the date of enactment of this section, publish a report that includes— (i) a description of the evaluation under subparagraph (A)