The Every Student Succeeds Act (ESSA), the most recent reauthorization of the Elementary and Secondary Education Act of 1965 (ESEA), requires that states test students annually in English Language Arts and Math in grades 3–8 and once in grades 10–12. States must also periodically test children in science. Prior to ESEA's previous reauthorization, the No Child Left Behind Act of 2001, ELLs were often left out of standardized testing for fear that their language skills might mask their content knowledge. While this was a legitimate concern, it also meant that there was also little accountability for ELLs’ growth.
The requirement that schools assess ELLs’ progress and report the results has shed light on this underserved population. However, these benefits have come as a result of unprecedented rates of ELL testing, and have been attached to aspirational federal mandates, such the law’s goal that students who are not yet proficient in English obtain proficient scores on content tests in English.
Students designated as recently arrived-LEP are not required to take (at most) one administration of state assessments in English Language Arts during their first 12 months in a U.S. school. This serves to momentarily take the pressure of off some ELLs (and to help teachers prioritize their acclimation to U.S. schools and the acquisition of basic English). However, research suggests that it can take ELLs as many as seven years to acquire the academic proficiency that is necessary to complete standardized assessments.
Teachers also engage in small-scale, non-standardized assessments on a regular basis in their classrooms, but these ongoing measures are more difficult to capture for large-scale data purposes. For more information, see these pieces on formative and informal assessments.