This post was last updated November 3rd 2013
What is USMLE Practice Test (Free 150) (USMLE CD)?
USMLE CD is the common name used by students and it refers to the Practice Test Exam available from the official USMLE website
Some people would like to call it the Free 150
It's used to be a CD that ships via mail, no longer a CD as it is now an instant online download.
You can find the download page for the latest 2013 tests for all the steps here in this page
USMLE Free Practice Materials
It is composed of three blocks of questions and it also has some extra orientation material similar to the ones that we see in the real exam. The Step 3 practice material also includes practice for the CCS part of the exam not only the MCQs. You can also do these questions in the Prometric testing center itself in what's called Prometric Practice Test
You cannot use the Free 150 on your MAC computer, you have to have Windows based computer and it's not compatible with the latest Windows 8 OS.
Is USMLE Practice Test useful?
Most of students will answer NO to this question. The reason being that the questions are much easier than the real exam and do not represent a real sample. However, there are others, who said that you may actually find exactly the same questions in the real exam. Also, there's a huge advantage of familiarizing yourself with the FRED2 software that is used by the USMLE to deliver the exam in Prometric centers. The Free 150 provides exact simulation of the exam software, USMLE World does provide similar experience but it's not as exact as the free 150.
Bottom line, we should all do these question to be on the safe side.
However, NBME forms, which are also made by the USMLE regulators provide much better real exam experience and it's highly recommended over the USMLE Practice test. For more information about NBME see this post
Are there Answers & Explanations?
Just like the NBME Forms the USMLE Practice test does not provide answers and explanation only analysis of your performance.
Can I predict my score from my Free 150 Performance?
Yes. Check these threads;
You can check the Free-150 tag link at the bottom of the thread for further information.