; (B) the provider directory accuracy scores trends under section 1857(e)(6) of the Social Security Act (as added by subsection (b)(1)), both overall and among providers specializing in mental health and substance disorder treatment; and (C) other items determined appropriate by the Comptroller General. (2) Report Not later than January 1, 2031, the Comptroller General shall submit to Congress, the Commissioner of Social Security, and the Secretary of Health and Human Services a report containing the results of the study conducted under paragraph (1), together with recommendations for such legislation and administrative action as the Comptroller General determines appropriate. 4. Guidance on best practices for maintaining accurate provider directories Not later than 12 months after the date of enactment of this Act, the Secretary of Health and Human Services shall issue guidance to Medicare Advantage organizations offering Medicare Advantage plans under part C of title XVIII of the Social Security Act ( 42 U.S.C. 1395w–21 et seq. ) on maintaining accurate provider directories for such plans. Such guidance may include the following, as determined appropriate by the Secretary: (1) Best practices for Medicare Advantage plans on how to work with providers to maintain the accuracy of provider directories of such plans and reduce provider and Medicare Advantage plan burden. (2) Information on data sets and data sources with information that could be used by such plans to maintain accurate provider directories. (3) Approaches for utilizing existing information assets of plans and publicly available data sets and data sources to maintain accurate provider directories. (4) Information that may be useful for beneficiaries to assess plan networks when selecting a plan and accessing providers participating in plan networks during the plan year.