What is the difference between random bias and systematic bias in automated systems, and how is each addressed?

• A. Random bias is a fixed shift; systematic bias varies.
• B. Random bias varies unpredictably; addressed with tighter precision QC; systematic bias consistent shift addressed by recalibration or method review.
• C. Both are corrected only by instrument replacement.
• D. Random bias is more dangerous.

Answer: (B)

Random bias is the kind of error that wanders from one measurement to the next without a fixed direction. It shows up as unpredictable fluctuations around the true value, so you can’t fix it with a single adjustment. The way to reduce its impact is through tighter precision quality control: more consistent instrument operation, tighter control limits, repeated measurements, and statistical process control to distinguish true signal from random scatter.

Systematic bias, on the other hand, is a constant or predictable offset from the true value. It shifts all measurements in the same direction, often due to calibration drift, reagent or protocol changes, instrument misalignment, or a biased calibration curve. Correcting this requires recalibration or method review, updating calibration standards, verifying with reference materials, and, if needed, instrument maintenance. Once recalibrated or the method reviewed, the consistent offset should be corrected or minimized.