Reliability is measured by what?

Reliability is measured by what?

• A. Consistency over time
• B. Correlation between measurements
• C. Mean differences between observers
• D. Standard deviation of error

Answer: (B)

Reliability is about consistency of measurements across repeated trials or raters. When a measurement is reliable, repeated readings under the same conditions tend to move together in the same way. The best way to capture that consistency is to look at the correlation between measurements taken on separate occasions (or by different observers). A high correlation means that the ordering of scores is stable across repeats, signaling dependable results. The other ideas describe related concepts but not the measure of reliability itself. Consistency over time describes what reliability aims for, but the actual metric used is the correlation between measurements. Mean differences between observers point to systematic bias, which undermines reliability but doesn’t quantify consistency. The standard deviation of the measurement error reflects how much error varies, but it doesn’t directly indicate how well two sets of measurements relate to each other.

Reliability is about consistency of measurements across repeated trials or raters. When a measurement is reliable, repeated readings under the same conditions tend to move together in the same way. The best way to capture that consistency is to look at the correlation between measurements taken on separate occasions (or by different observers). A high correlation means that the ordering of scores is stable across repeats, signaling dependable results.

The other ideas describe related concepts but not the measure of reliability itself. Consistency over time describes what reliability aims for, but the actual metric used is the correlation between measurements. Mean differences between observers point to systematic bias, which undermines reliability but doesn’t quantify consistency. The standard deviation of the measurement error reflects how much error varies, but it doesn’t directly indicate how well two sets of measurements relate to each other.