MCID calculator

What the two thresholds mean

MDC, the minimal detectable change, is the smallest change that is larger than the error in the measurement itself. A change below it may be the test, not the client.

MCID, the minimal clinically important difference, is the smallest change a client would notice as worthwhile. It is estimated from a study population, and it varies between populations and between methods, which is why this page asks which population you mean and names the paper each number comes from.

Both are study estimates about groups. Neither decides anything about one person in front of you. That judgement is yours.

Where the numbers come from

Every threshold on this page is read from a published paper, transcribed with its citation, population and method, and used only after a human has checked it against that paper. Nothing is estimated, averaged or filled in from memory, and a test with no checked row for your population says so rather than offering a number from somewhere else.

57 thresholds have passed that check so far. Rows that did not are not on this page: some because the paper could not be opened to confirm the figure, and some because the authors themselves said the number was not a reliable estimate for that group.