While many educators expect the Common Core State Standards (CCSS) to be more rigorous than previous state standards, some wonder if the transition to CCSS and to a Common Core aligned MAP test will have an impact on their students' RIT scores or the NWEA norms. MAP assessments use a proprietary scale known as the RIT (Rasch unit) scale to measure student achievement and growth. The RIT scale, based on item response theory (IRT), has been used since the late 1970s by NWEA and is a proven, stable scale for educational assessment. The principle behind the RIT scale is simple: Test questions vary in difficulty and can be given a score on the RIT scale. A student's achievement level can then be measured on the same scale by referencing the questions they were able to answer correctly. Every item in MAP tests is calibrated against one of the stable RIT scales: Reading, Language, Math or Science. Student responses on these items are used to generate a final RIT score for each student. An individual item with its associated RIT value may appear in tests aligned to various learning standards, such as state standards and the Common Core State Standards. Regardless of the standards alignment of a particular test, a given item has a single RIT value associated with it. This RIT value is obtained using a rigorous calibration process in which each item is field tested with thousands of students across the nation. The purpose of MAP tests is to measure growth by examining RIT scores over time. If two different MAP tests are on the same scale (e.g. Math) and measure similar constructs, then scores for these two tests can be compared directly. MAP tests aligned to CCSS, as well as other state standards (state-aligned) on a given scale, measure similar constructs due to the high degree of content overlap among learning standards. This underlying design of MAP tests is critical to ensuring that RIT scores carry the same meaning, in terms of student ability, regardless of which test was used to obtain them. Because the RIT scales are independent of standards alignment, transitioning between two tests is not anticipated to have a significant impact, however, States that are transitioning (or who have already transitioned) to teaching the CCSS, and are working to understand the gap between their state standards and what's required by the CCSS, are seeing some key shifts. Those shifts are detailed in this report, and questions and answers are provided.