People take them to know where their weaknesses are, ie. for Physics, it'll tell you if you're weak on force topics and/or waves. After you're done with each topic, it'll tell you what percentage of students who took it are below/above you just to get an idea of where you stand. I would recommend doing them once you're done with your content review since you can only take them one time and you want to have a decent background so you'll know what you need to focus on after you take them. You can get it through the aamc website..think it's like $109 for all 5 subjects (bio, ochem, phys, chem, verbal) or get them individually. Like the AAMC tests, you can read up on the explanation after you take it but unlike the AAMC tests, you're only allowed to take them once. I wouldn't really use it to learn content from though..it's just good practice and analysis of where you stand.
