Distinguish between these easily confused terms: calibration, verification, adjustment, and validation

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1 Definition: Calibration: The process of compensating for systematic errors in an instrument by measuring the deviation of a standard, thereby improving the accuracy (precision) of the instrument or system. Calibration is generally used for instruments with high precision. Verification: An activity carried out in accordance with **metrological verification regulations, through experiments, to determine whether the indication error of measuring instruments meets the required standards. The scope of verification refers to the measuring instruments subject to mandatory verification as specified by China’s Metrology Law. Calibration: The process of determining the indicated value of a measuring instrument through experiments, in accordance with relevant calibration standards. Typically, the error of the instrument under measurement with respect to a higher-precision standard is determined by making comparative measurements, thereby obtaining a correction value for the reading of the instrument under measurement. Calibration is mainly used for measuring instruments that are not subject to mandatory verification. Verification: A method of establishing traceability for value transfer when there are no relevant testing procedures or calibration specifications, by following methods developed by the organization itself. It is mainly used in specialized measuring instruments, or measuring instruments with relatively low accuracy. 2 Meanings and differences I. Meaning of calibration: It involves using standard measuring instruments to check whether the accuracy (precision) of the instrument in use meets the standards. This is generally applied to instruments requiring a high degree of precision. Primary function: 1. Determine the input-output relationship of an instrument or measurement system, and assign a division value to it ； 2. Determine the static characteristic parameters of the instrument or measurement system ； 3. Eliminate systematic errors and improve the accuracy of the instrument or system ； 4. In scientific measurements, calibration is an important step that cannot be ignored ； II. Meaning of verification: A method for tracing the traceability of measurement values, which is implemented in accordance with procedures developed by the organization itself when there are no relevant testing regulations or calibration standards available. It is mainly used for specialized measuring instruments, or measuring instruments with relatively low accuracy, as well as the hardware or software for testing. III. Meaning of calibration: It is an activity carried out by legal metrology departments or organizations authorized by law, in accordance with calibration procedures and through experiments, to provide evidence confirming that the indication error of measuring instruments meets specified requirements. IV. Meaning of calibration: Under specified conditions, in order to determine the reading of a measuring instrument or measurement system, or the value represented by a physical measuring tool or reference material, high-precision, certified standard equipment and the device under calibration are used to test the same quantity being measured. This process yields a set of values indicating the error of the device under calibration relative to the standard equipment, thereby allowing for the correction of the reading values of that device. V. Main differences between calibration, verification, and testing 1. Calibration is a dynamic process that takes place during measurement, aimed at verifying the accuracy of testing equipment and eliminating errors in a timely manner. 2. Verification, calibration, and validation are static metrological processes that are carried out on a periodic basis. 3 The main differences between verification and calibration: (1) Different purposes. The purpose of calibration is to assess the indication error of a measuring device by comparing it with a measurement standard, in order to ensure the accuracy of the measured values; it constitutes a set of operations for tracing values from lower to higher levels. The assessment of such indication error shall be specified in accordance with the organization’s calibration procedures, carried out at regular calibration intervals, with proper calibration records and markings kept. WeChat official account: Lab ISO17025 Reminder. In addition to assessing the indication error of measuring devices and determining relevant metrological properties, calibration results can also be expressed as correction values or calibration factors, which provide guidance for the operation of measurement processes. For example, if a caliper used by a machining company is found to be 0.2 mm off from the standard value after calibration, this figure can be used as a correction value; the calibrated value along with the 0.2 mm deviation relative to the standard should be indicated on the calibration label and records. During the actual measurement using this measuring instrument (caliper), by subtracting a correction value of 0.2 mm for the excess, the resulting value represents the actual measured value. As long as the purpose of value traceability is achieved and the indication error of the measuring instrument is clearly understood, the purpose of calibration is fulfilled. Purpose of the inspection: To conduct a mandatory comprehensive evaluation of the measuring device. This comprehensive evaluation falls under the category of value unification; it is a top-down process of value transfer. The verification shall determine whether the measuring instrument meets the specified requirements. This requirement refers to the error range specified in the calibration procedures for the measuring device. Through testing, it is determined whether the error range of the measuring device falls within the specified range. (II) Different objects: The objects for calibration are measuring devices that fall outside the scope of mandatory verification. Measurement devices in our country that are not subject to mandatory verification mainly refer to measuring instruments that are widely used in the processes of production and service provision, including those used for incoming material inspection, in-process inspection, and final product inspection. The objects of verification are the measuring devices subject to mandatory verification as clearly stipulated in our country’s Metrology Law. Article 9 of the Metrology Law of the People’s Republic of China stipulates clearly: “The metrology administrative departments at or above the county level shall enforce mandatory inspection on social public metrological standard instruments, the highest-level metrological standard instruments used by departments, enterprises, and institutions, as well as working metrological instruments that are included in the list for mandatory inspection and are used in areas such as trade settlement, safety protection, medical and health care, and environmental monitoring.” It shall not be used if it has not been submitted for inspection as required or has failed the inspection. ” (III) Calibration of different natures is not mandatory; it is a voluntary traceability action undertaken by organizations. It is a technical activity that involves assessing the indication error of measuring instruments according to the actual needs of an organization, and it is a process for determining the values of measuring instruments or reference materials. An organization may specify calibration specifications or calibration methods according to actual needs. Setting the calibration cycle, calibration markings, and records on one’s own is not permitted; calibration is a mandatory regulatory action that falls under the scope of legal metrology management. All aspects such as the agreement period for the inspection procedures are carried out in accordance with legal requirements. (IV) Different cycles: The calibration cycle is determined by the organization itself based on the needs of using the measuring instruments. It can be calibrated regularly, irregularly, or before use. The principle for determining the calibration cycle should be to maintain minimal calibration costs while minimizing the risks associated with the use of measuring equipment. The calibration interval can be determined based on the frequency of use of the measuring instrument or its level of risk. WeChat official account: Lab ISO17025 reminder – the calibration cycle must be determined in accordance with the provisions of the Calibration Procedures; the organization cannot decide it on its own. The calibration cycle is a matter of mandatory compliance. (V) Conclusion: Different calibration methods are used solely to assess the numerical error of measuring devices and ensure accuracy of the values; they do not require a determination of whether the device is qualified or not. The results of calibration can be provided as a \"Calibration Certificate\" or a \"Calibration Report\". The verification must, based on the permissible range of value errors stipulated in the “Verification Regulations”, determine whether the measuring device is qualified or unqualified. Values with an error exceeding the range specified in the “Verification Regulations” are considered unacceptable; those within the specified error range are acceptable. The result of the inspection is a \"Certificate of Inspection Approval\". 4. Options for verification, inspection, and calibration: 1. The \"Announcement by the State Administration for Market Regulation on the Publication of the List of Measuring Instruments Subject to Mandatory Control (No. 48, 2019)\」clearly stipulates this. 2. As of the date of issuance of this announcement, measuring instruments listed in the List and for which the control method is V (mandatory inspection) or P+V (type approval + mandatory inspection) must undergo mandatory inspection during use; other measuring instruments are no longer subject to mandatory inspection. Users may choose either non-mandatory inspection or calibration to ensure the accuracy of their measurement values.