; (2) housing instability; (3) transportation access; (4) safety; (5) social connection and isolation; (6) financial resource strain; and (7) stress. (b) Activities The activities of the demonstration program under this section shall include: (1) Assessing the availability of identified and deidentified data sets held by Federal, State, local, and non-Federal entities that may be useful for research described in subsection (a). (2) Using existing authorities and linkages of data in accordance with subchapter III of chapter 35 of title 44, United States Code, when relevant to request the submission of datasets to the National Center for Health Statistics for linking. (c) Limitation The Secretary shall limit access to data under the demonstration program under this section— (1) to Federal statistical agencies and qualified public and private researchers, as determined by the Director of the National Center for Health Statistics; (2) for a period to be specified by the Secretary; and (3) exclusively for the purpose described in subsection (a). (d) Process for making data available (1) In general Consistent with paragraph (2), the Secretary shall establish a rigorous process for making data available and usable pursuant to the demonstration program under this section. (2) Requirements Before any data is made available pursuant to the demonstration program under this section by an entity described in subsection (b)(1) to another entity described in subsection (b)(1)— (A) the receiving entity shall submit to the Director of the National Center for Health Statistics an application for data for the purpose described in subsection (a); and (B) the Director shall approve or deny such request in writing, including in the case of a denial an explanation of the reasons for the denial. (e) Rulemaking (1) No delay on implementation The Secretary— (A) shall begin implementation of the demonstration program under this section upon the date of enactment of this subtitle