Unknown is a legitimate review state

Public files do not always contain enough information to settle a question. A row can pair a zero count with populated statistics and still be correct, if the charge is fully calculable as a dollar amount. From the outside, we cannot always tell which case we are looking at.

The honest state for those rows is unknown. Forcing every flagged row into pass or fail manufactures certainty the evidence does not support, and it is how review candidates turn into unsupported accusations.

Keep unknown as a first-class outcome with its own count. Rows stay there until someone with the contract or the remittance history can settle them. A review queue that admits what it cannot prove is more useful than one that guesses.

Read the original research: When a zero count has a median.

Sources: CMS FAQ; CMS technical documentation.