The ESTAR and MSTAR Diagnostic Assessments are designed for those students who are at risk for not being ready for algebra. This includes students in Tiers 2A, 2B, 3A, and 3B. ESTAR and MSTAR Diagnostic Assessments are designed to give you detailed information about student understanding. In order to provide reliable information, each diagnostic assessment is longer than the MSTAR Universal Screeners, ranging from 25 to 55 questions. Because of the length of time it takes to administer an assessment, only those students who are at risk should be given one.