These reports are required by G.L. c. 18B, Section 25 (see https://malegislature.gov/Laws/GeneralLaws/PartI/TitleII/Chapter18b/Section25).
The commissioner is to report on a quarterly basis on the total number of cases of multiple 51A reports reviewed by the department under subsection (r) of section 51B of chapter 119, the types of those cases, and their resolutions. The report shall be filed with the governor, the clerks of the senate and the house, the joint committee on children, families and persons with disabilities, and the child advocate.
DCF has published one report that is publicly available, in April 2016.