Tree pattern application with more attributes for top parent node

I am modeling a examination assessment where each test will have be scored based on some major criteria and each of those will be divided further into various subcategories and those subcategories are further subdivided recursively. Each tree node will have a max score and weightage among siblings, parent node reference, etc.,.
My question is only top level node will have more attributes. How do we model this, If if store all attributes in all nodes, its a lot of repetition/duplicates, if we keep those fields in a separate collection, it requires a reference match.