Which term refers to the comparison between an instrument and a more accurate standard to check if it meets specifications?

The term that accurately describes the process of comparing an instrument to a more precise standard to ensure it meets specified accuracy is calibration. Calibration serves as a critical quality assurance measure in various scientific and technical fields, including forensic analysis. By systematically aligning an instrument's measurements with those of a recognized standard, calibration helps to confirm that the instrument produces reliable and valid results. This process often involves adjusting the instrument to correct any deviations and to ensure that it operates within specified parameters.

The other terms do not fit this specific concept. Validation generally refers to the process of assessing whether a method or procedure meets the required specifications for its intended use, but it does not specifically involve the direct comparison to a standard. Anecdotal evidence refers to personal accounts or stories that may provide insight but lack rigorous testing or statistical validation. A sample refers to a subset of a whole, but does not encompass the idea of measuring against a standard for accuracy. Therefore, calibration is the precise term for the practice described in the question.