Origin, Purpose, Value and Limitation (OPVL) is a technique for analyzing historical documents. It is used extensively in the International Baccalaureate curriculum and testing materials, and is incredibly helpful in teaching students to be critical observers. It is also known as Document Based Questions (DBQ).
Author's Note: Thanks to Melissa for the OPVL heads up...
My hope is that The Playground will be used as a took to discuss modern day geopolitics. Feel free to contact me: firstname.lastname@example.org
Download the pdf from here