I agree with Pat. In my rescue company, we are required to run at least 15 "aidman" calls after EMT-B (thats basic in MD)training. This means that in addition to assisting the aidman on calls in general, you need to actually comand 15 calls, under supervision, sucessfully, before you are granted full aidman status. This allows you to really get a feel for the different calls that can happen. We also have to run as medic assists (on the ALS units) a certain amount of times and then, take an aidman trauma scenario test. After this, we are granted the rank of PRIVATE, and are fully capable of running and commanding calls.