monitoring lessons

One way that I monitor my lessons is to ask my students whenever there is some confusion if they understand.  I ALWAYS ask for non-verbal responses to yes and no questions so using this technique is a quick way for me to gauge is I should move forward or continue explaining.  This way I can keep the lesson at the pace the students need it to be.  Recently I have experimented with allowing students who understand the instructions to return to their desk and begin working and the students who need further explanation to remain on the carpet.  This has worked really well.  The only downside is that not everyone finishes at the same time.  The positive side is that students who understand aren't getting restless on the carpet causing interruptions and that I can give these students additional assignments occasionally.   I would use this strategy again, but that choice would be made on a case by case basis.