Table 1.

Calculation formula of MCID based on anchor method.

Standard	Sample size n	Anchor difference D (Q29 Score difference)	Scale field score difference d	Mean ( $\overline{\left|d\right|}$ )
A: One level away	n1	D 1=X1- X0=±1	x1-x0	$\frac{d_1+d_2+\dots +d_{n_1}}{n_1}$
B: At least one level away	n2	D 2=X1-X0=±1,2,3,4,5,6	x1-x0	$\frac{d_1+d_2+\dots +d_{n_2}}{n_2}$