What is a primary indicator that the HGN test is being improperly administered?

The correct choice highlights that inconsistent officer instructions during the HGN test can significantly compromise the effectiveness of the evaluation. The HGN test is designed to measure a subject's eye movements, looking for specific cues that indicate impairment, often due to substances like alcohol. For the results to be valid and reliable, it is crucial that the officer administers the test consistently, adhering strictly to standard procedures.

When instructions vary from one test to another, or if the subject does not receive clear and uniform guidance, the results may be skewed. Subjects could misunderstand what is required of them, leading to confusion and potentially inaccurate readings of their eye movements. This inconsistency can affect the assessor's ability to accurately interpret the results, ultimately undermining the purpose of conducting the test. Thus, maintaining a standardized approach in administering the instructions is vital for the integrity of the HGN assessment.