How would I devise a rubric to evaluate an essay on which character in Animal Farm would make the best leader?
Also, I need to ask the students to give their opinions about the qualities which are required to make a good leader, and to list some of the characters in the book who have leadership potential based on this assessment. All of this should be on the rubric.
Taking as many insights as possible from people outside your classroom setting is great on creation of rubrics. It will get you thinking about what you want your students to write and this will help create better thought on the part of your students and a healthier dialogue on the text for both of you. Having said that, I strongly suggest that you reflect on what you want the students to display in their writing. For this, you have to be the source of how your in class discussions have gone, where you have seen them move in your progress monitoring, and think about upon what you want them to focus their writing.
I think that the form of this rubric could take many levels. Perhaps you have a 4- 3-2-1 format. A "3" means that the student met the standard and fulfilled the requirements, while a "2" means that they came close to it, but missed some elements. A "1" means significant work is needed, while the "4" represents student work that really went above and beyond in both expression and content. Obviously, part of your rubric will be that the students identified a character in the book that would make the best leader. The next area of your rubric might focus on how they merge their opinion with substantiation from the text about their choice. You can also include a section for the five qualities that the students think make a good leader and then assess them on how well they substantiate their ideas. Finally, the last part of your rubric could be on how the leadership potential element exists with different animals on the farm.
There is much here for the students to write their essays. If I could offer one piece of advice on creating rubrics in this light, it would be that the more focused the rubric, the better the writing will be. If the rubric is all over the place in terms of what it's assessing, I think that it's pretty clear that the student writing will be, also. Harness your thoughts in terms of what you want the students to write about. Clearly state this to them and delineate it on the rubric. Go over the rubric with them before they start writing and then see how things progress with rough drafts, writing conferences, and personalized help. All the while in these formats, the rubric should be there to guide your helping of them. A streamlined topic area will feed into a streamlined rubric and generate streamlined writing from your students.