Which statement best defines accuracy in measurement?

• A. Closeness to the true value.
• B. Repeatability of measurements.
• C. Stability of readings over time.
• D. Ability to measure across a wide range.

Answer: (A)

This question is about how accuracy in measurement is defined. Accuracy is about how close a measurement is to the true value. If a measurement lands near the actual quantity you’re trying to measure, it’s accurate.

Understand the distinction: precision is about repeatability—the measurements clustering tightly together, regardless of proximity to the true value. A device can be very precise (consistent results) but not accurate if those results are biased away from the true value. Stability over time describes whether readings drift or stay constant, which is about changing results, not how close those results are to the true value. Wide range describes the instrument’s dynamic range, not its accuracy.

So the best definition is closeness to the true value. For example, measuring a known standard that should be 100 units and getting readings like 99.8 or 100.2 shows accuracy, whereas consistently getting 95.0 would be precise if tightly clustered but not accurate due to bias.