Accuracy and precision are the cornerstones of reliable scientific research or lab results. Even the most trivial error in the data accuracy and measurement can lead to poor calibration or consistency of results.
Let’s delve deeper into measuring and improving lab accuracy and precision.
Understanding the Difference
Accuracy refers to the closeness of the measured value to a standard, accepted, true or known value. For example, the weight of a substance you measured is 1.970 kg and the standard value is 2 kg. This means measurement is quite accurate.
Precision refers to the closeness of replicated (at least two or more) measurements. For example, if you measure a substance three times and you get 500 grams every time, then it is a precise result.
However, it is important to know that accurate results may not be precise and a precise result may not be accurate. So, even if you get 500 grams in every measurement, it is still far from the accepted value of 2 kg.
Improving Accuracy and Precision
While you aim for 100% accuracy and precision, remember that bias and factors outside your control can make it difficult to achieve. However, you can maximise both through the following ways:
1. Reference Standards and Repeatability
Take standard samples and true values for measurement for higher accuracy. Use high-quality or certified references.
Repeatability is the key to getting precision. Conduct the experiments multiple times over several days under the same and consistent conditions. Try to measure using different operators, equipment and labs.
2. Calibration of Instruments
Calibration – the act of testing, standardising and adjusting the instruments or equipment to eliminate bias in the readings. It enables the comparison of a standard measurement to an instrument’s measurement. Calibration should be done before the beginning of the experiment when results are unconvincing or the instrument went through some damage. Refer to user manuals or seek the help of professionals for calibration.
3. Equipment Maintenance
Regular upkeep of equipment not only prolongs its longevity and lowers safety hazards, but it also gives reliable and consistent results. It ensures the validity of results and correct conclusions.
4. Standardisation of Protocols and Procedures
Make sure to abide by the lab protocols and standard operating procedures (SOPs). The protocols will help in experimenting according to the set of instructions. SOPs will ensure consistency and compliance in the lab. This standardisation will minimise human errors and adopt consistent techniques, thereby bringing the desired accuracy and precision.
5. Measurement System Analysis (MSA)
Use the statistical tool called MSA to evaluate or quantify the amount of variation in the measurements. It can be instrumental in determining the source of variation – equipment, operator or lab environment.
It improves accuracy in terms of bias, linearity and stability. It improves precision in terms of repeatability and reproducibility.
6. Reference Ranges
Variability in results may occur across labs, equipment, analysis techniques or the use of chemical reagents. Consequently, the accuracy that seems normal in one experiment may become abnormal in another one.
It is necessary to set an appropriate reference range to accommodate variations within relevant control variables.
7. Recheck / Take Several Measurements
If you find inconsistency in the results, it is advisable to double-check or triple-check. It is quite likely that you may spot the error or abnormality such as poor calibration of equipment, wrong equipment or faulty reference range. You may also want to re-examine your test assumptions and hypothesis.
You can also consider running duplicates or triplicates to detect outliers in case of a limited sample size.
8. Human Error Minimisation
The skills, experience and techniques of operators are directly linked to the accuracy and precision in the labs. Ensure that the operators are adequately trained to handle and calibrate the equipment, follow protocols and SOPs, correctly read and interpret the values, record the values correctly, etc.
You can consider using automation and AI-driven analytics, especially for large-volume tests to reduce manual handling.
9. Environmental Conditions
Environmental factors such as air currents, moisture, vibrations, temperature and humidity can cause variations in precision and accuracy. Conduct the experiments in a controlled lab setting.
Conclusion
Accuracy and precision in measurements ensure data integrity and improve the quality of results. This further enables better and insight-driven decision-making. Hence, one must undertake all necessary steps for the best possible accuracy and precision.
