Which area is not a subjective area of the 1995 Documentation Guidelines (DGs)?

The correct answer pertains to an area that is not influenced by personal feelings or opinions, which is essential when differentiating between subjective and objective elements in medical documentation. In the context of the 1995 Documentation Guidelines, the analysis of "unit metrics" is based on quantifiable data and objective measurements rather than personal interpretation or judgment. This aligns with the standards for consistent and reliable metrics in clinical documentation, which rely on factual information rather than subjective assessments.

In contrast, the other areas mentioned in the question inherently involve subjective interpretations. For example, differentiating between an Expanded Problem Focused and a Detailed exam involves interpreting clinical findings and the seriousness of presenting problems, which can vary based on the clinician’s perspective. Similarly, defining a Comprehensive single system exam requires an understanding of varying degrees of detail and clinical complexity, reflecting a clinician's subjective evaluation of the patient's condition. Analyzing historical patient data also incorporates subjective judgments regarding relevance and significance, as the clinician assesses past medical information to guide current decision-making.

Thus, only the comparison of unit metrics stands apart as it is objective, making this choice the correct response to the question.