Protecting human research subjects is an ethical mandate for all contemporary research involving human subjects. From 1974 to 1999, we had the institutional review board (IRB) system and the Common Rule, but realized that in addition to IRBs, investigators, institutions, sponsors of research, research participants, and the government, all share responsibilities in protecting human research subjects. Starting 2000, institutions established human research protection programs to ensure the rights and welfare of research participants and to meet human research ethical and regulatory requirements. Some institutions had their human research protection programs further accredited to ensure rigorous standards for quality and protection. In 2018, the Common Rule was extensively revised to modernize the regulations by enhancing protections and reducing burden for researchers. However, throughout these periods, we did not know how well we were protecting human research subjects, because we did not know how to measure human research subject protections. With the publication of human research subject protections performance metrics in 2023, it becomes possible for the first time to assess quantitatively how well we are protecting human research subjects. Research institutions can now monitor the effectiveness of their human research protection programs and identify areas of vulnerability for quality improvement. We should also be able to determine how well human research protection programs are doing in protecting human research subjects; determine whether external accreditation improves human research subject protections and whether the revised Common Rule in fact leads to enhanced protections; and identify prospectively which procedures or interventions can enhance human research subject protections.