commentary vs position paper

commentary

noun
  • A series of comments or annotations; especially, a book of explanations or expositions on the whole or a part of some other work. 

  • An oral relation of an event, especially broadcast by television or radio, as it occurs. 

  • A brief account of transactions or events written hastily, as if for a memorandum. 

position paper

noun
  • An essay or report which expresses a position, conclusion, or recommendation concerning a contested issue or undecided question and which usually contains arguments or reasons in support of this position. 

How often have the words commentary and position paper occurred in a corpus of books? (source: Google Ngram Viewer )