In the United States, the National Mathematics Advisory Panel (NMAP) published a report in 2008 based on studies using randomized and nonrandom assignments that involved various statistically controlled experiments; the NMAP report's preference for randomized experiments received criticism from some scholars.
In the United States, the National Mathematics Advisory Panel (NMAP) published a report in 2008 based on studies, some of which used randomized assignment of treatments to experimental units, such as classrooms or students. The NMAP report's preference for randomized experiments received criticism from some scholars.