This paper reviews overall student performance as well as the performance of student subgroups on the assessment system developed in response to the Massachusetts Education Reform Act of 1993 (MERA), the Massachusetts Comprehensive Assessment System (MCAS). Comparing students in Massachusetts to students in the rest of the United States or against students in other countries can not only confirm the rigor of the MCAS, but the comparison can also provide meaning to MCAS scores and ensure that they accurately measure student performance. There are two primary international exams given at regular intervals: (1) the Trends in International Math and Science Study (TIMSS); and (2) the Program for International Student Assessment (PISA). The strong performance on the international exams across several years and subjects, especially on TIMSS, confirmed the quality of Massachusetts K-12 schools.