CMS 871 DENOM Observation value error : Expected DENOM Observation value does not match reported value. The problem was with the <id root="8C95B101-3C3C-40E6-B12A-9002768CE2CE" /> value. I think this <id root> value is predefined/standard value. It is working for the NUMERATOR observation value. But I am getting same error with the DENOM observation value. Please let me know where can I find these predefined/standard id root values for each measure elements.