AIMSweb/plus is intended for more frequent progress monitoring than MAP, which should be used no more than three times a year. However, AIMSweb's progress monitoring is really useful only for the at-risk population; it's designed with more floor than ceiling.
In general, universal screening instruments are not particularly helpful for discriminating within the top 10 percent (since most of them use 90th %ile, or even lower, as the cutoff for "high achiever" range). From the standpoint of instructional groupings in a differentiated instruction model, this is sufficient discriminatory power, as that is only 2-3 students out of the typical classroom, which might come to 10-20 students per grade in a medium-to-large sized elementary school.
