Classification Of Measurement Errors

The study of Physics encompasses experimentation and measurement to confirm theoretical validity. Measurement enables the comparison of different objects. In experiments, one object has a predefined quantity while the dimension of the other object is yet to be determined. Furthermore, this mathematical concept simplifies the explanation of Physics principles. Nominal values are clear, convenient techniques for presenting concepts and principles. Scientific measurements follow the International System of Units (SI units) to record data, perform calculations, and report results. Measurement also enhances the understanding of mathematical and physics concepts. Errors may arise during experimentation. This article details the classification of errors in measurement.

Definition of Measurement

Measurement involves representing quantities of various attributes with a real-time system and using numerical values. This mathematical concept compares the quantity of unknown dimensions and a predetermined ‘ideal’ standard.

When making measurements, some degree of error may occur for multiple reasons. The evaluation in the classification of error in measurement obtained from a measurement result is uncertainty or error analysis. Mathematical analysts and physicists employ the concepts of accuracy and precision to test the amount of error associated with a measurement.

Accuracy refers to how a measured value relates in close agreement with a predefined value. The extent of error represents the amount of inaccuracy. Furthermore, the proportion of consistency among independent measurements of the same dimension is known as precision.

Some standards exist to ensure an accurate measurement. These include the use of accurate apparatus, the implementation of accurate predefined standards, and the application of a provable method.

The classification of error in measurement builds on accuracy and precision.

Classification of Errors in Measurement

The definition of error is the difference between the actual measured value and the true predetermined value. The classification of error in measurement features three main categories. These are systemic, random, limiting, and gross errors.

• Systemic errors

These errors are caused by environmental changes, instrumental faults, and wrong observations. Systemic errors are further classified as instrumental, observational, and environmental errors.

• Instrumental errors

They occur due to faulty instruments, improper use of apparatus, or instrumental loading effect. Moreover, imprecision in the assembly, calibration, or operation is the source of intrinsic errors. These miscalculations are easily detectable. Their correction involves the recalibration and meticulous planning of the measurement process.

• Observational errors

Parallax error occurs due to misalignment between the line of vision and the pointer on a scale. Observational errors are common in analogue instruments. Therefore, using digital display apparatus with highly accurate metres guarantees the prevention of these errors.

• Environmental errors

The external conditions may affect the instruments’ functioning. These circumstances include temperature, dust, humidity, vibrations, and electromagnetic fields. The various corrective measures implemented in environmental errors include maintaining a constant surrounding, using highly resistant apparatus, and computing corrections. 

• Random errors

Random errors happen as minute factors change from one measurement to another. The detection of these errors is difficult as the sources of miscalculations are unknown. Physicists apply statistical terms to resolve these errors. These terms encompass the calculation of arithmetic mean, range, standard deviation, and variance.

• Gross errors

During experiments, manual errors occur because of faulty reading apparatus or recording false results different from the actual measurement. These miscalculations are unavoidable as they are caused by human influence. People can prevent these errors through careful reading and data recording and taking multiple readings. 

• Limiting errors

Factors such as the type of material impede maximum accuracy. These factors occur during the manufacturing process. Therefore, the manufacturer guarantees a specific percentage of accuracy. These miscalculations are also known as guarantee errors. Furthermore, the proportion of error to the predetermined numerical value determines the relative limiting error.

Sources of Error in Measurement

Knowledge of the different sources of misreadings in the classification of error in measurement is beneficial in their prevention and resolution. Below are the various sources of error according to the classification of errors in measurement.

Systematic sources of errors

• Incorrect calibration of instruments.

• Zero offsets in devices such as micrometre calliper and electronic balance.

• Instrument drift is caused by gradual changes in the function of an apparatus.

• Failure to specify and control all possible factors, excluding the independent variable under investigation.

Random sources of errors

• Physical variations of instruments.

Systemic and random sources of error

• Environmental factors in the working environment.

• Parallax errors when recording measurements.

• Lack of consideration of the conditions that may affect the measurement.

Gross sources of error

• Carelessness in the form of incorrect measurement.

• Implementation of poor techniques in the measurement process.

• Bias by expecting a particular result.

Conclusion

Experiments and measurements support the basic concepts of Mathematics and Physics. Measurements increase our understanding of theories. They also serve as a benchmark for the testing of various scientific theories. Measuring different objects allows us to compare various dimensions in real-time using numerical values. Errors may arise during the measurement process due to an assortment of factors. The classification of errors in measurement gives rise to four main types of errors. These include systemic, gross, random, and limiting. The causes and resolutions of these errors differ. The common causes of errors are the parallax phenomenon, faulty equipment, and incorrect methods of experimentation.