Which type of error affects accuracy?

• A. Random error
• B. Systematic error
• C. Calibration error
• D. Deterioration of reagent

Answer: (B)

Accuracy measures how close a measurement is to the true value. A bias that keeps results consistently away from that true value is the hallmark of a systematic error. Because systematic error shifts every measurement by roughly the same amount (like a miscalibrated instrument that reads consistently too high), it directly degrades accuracy. In contrast, random errors cause results to scatter around the true value, which mainly reduces precision rather than producing an ongoing bias in accuracy. Calibration issues are a common source of systematic error, while deterioration of reagent can introduce bias or variability but the key idea for accuracy is the persistent bias that systematic error represents.