Yes, the OG Diagnostic features some of the more challenging problems in the book and is a good benchmark for what type of questions you're likely to need to focus on more. That said however, the OG Diagnostic does not tell you about your strengths/weaknesses in specific content areas that the GMAT tests you on.
My suggestion would be to take the Free
Manhattan GMAT CAT and spend some time reviewing the "Assessment Report" to see what specific content areas you need to spend more time on.
hardaway7
Hello-
I am just starting to study using the OG Guide- Did anyone find the Diagnostic Test to be a helpful and reliable study strategy?
Thanks!