I offer this lesson as a "final exam" in my course at semester's end. The assessment described requires students to reflect back on the previous semester's worth of writing and to answer some specific questions in self-reflection.
I have found over the years that this assessment is often one of the most rewarding, and, if you believe like I do that grades ought to be based on learning and not necessarily achievement, you will appreciate borrowing my example or creating one that is similar.
Students need access to their Research Notebook Portfolio page, so you will want to write this in an internet connected lab setting (which is easy to book at many schools, given the labs light use during exams). (There is an attached screencast resource re: revisiting the portfolio page.)
I have prepared students in the days beforehand to think about the assessment, but on exam day, they will see the actual "prompt" for the first time. (The link is to a Google Doc copy of the final task, but I have attached it to my lesson write-up as a resource.)
Once I distribute the assessment in paper form, I ask them to read it thoroughly and "look up" when they have done so. Then, I know we can proceed.
After I distribute the hard-copy instructions, I start a timer. I generally give students about 45 min. to write, as this is typically 1/2 of our 90 minute exam period and, inevitably, they will need some time to finish the semester-ending Policy Presentations.
During this time, I circulate around the lab, reading bits and pieces of the essays as they are assembled. I try to offer as much encouragement as possible, remaining sensitive to the idea that they should be reflecting "unfettered."
When they have finished they share (via Drive), and I file these for evaluation as part of the final exam grade ...
Here are two student samples: