MDC definition.

MDC definition.

• A. Minimal Detectable Change
• B. Maximum Detectable Change
• C. Median Detectable Change
• D. Minimal Deviation Change

Answer: (A)

The concept being tested is distinguishing real change from measurement error in repeated measurements. Minimal Detectable Change is the smallest amount of change that exceeds the instrument’s measurement error with a chosen level of confidence. It’s calculated from the standard error of measurement, which captures how much scores can vary due to the tool’s unreliability. For a 95% confidence level, you multiply the SEM by 1.96 and by sqrt(2) to account for two measurements (pre and post), giving MDC95 = SEM × 1.96 × √2 ≈ SEM × 2.77. If the observed change exceeds this threshold, you can be about 95% confident that the change is real, not just random noise. This is different from the clinically important difference, which focuses on whether the change is meaningful in a practical, clinical sense rather than simply beyond measurement error. The other terms listed aren’t standard definitions for MDC.

The concept being tested is distinguishing real change from measurement error in repeated measurements. Minimal Detectable Change is the smallest amount of change that exceeds the instrument’s measurement error with a chosen level of confidence. It’s calculated from the standard error of measurement, which captures how much scores can vary due to the tool’s unreliability. For a 95% confidence level, you multiply the SEM by 1.96 and by sqrt(2) to account for two measurements (pre and post), giving MDC95 = SEM × 1.96 × √2 ≈ SEM × 2.77. If the observed change exceeds this threshold, you can be about 95% confident that the change is real, not just random noise. This is different from the clinically important difference, which focuses on whether the change is meaningful in a practical, clinical sense rather than simply beyond measurement error. The other terms listed aren’t standard definitions for MDC.