Agreement

General idea The Concordance Correlation Coefficient (CCC) is a statistical measure designed to evaluate the agreement between two sets of measurements, such as those represented by two random variables, $X$ and $Y$. Mathematically, the CCC is defined as: $$\rho_c = \frac{2\sigma_{x,y}}{\sigma_x^2 + \sigma_y^2 + (\mu_x - \mu_y)^2} = \frac{2\rho\sigma_x\sigma_y}{\sigma_x^2 + \sigma_y^2 + (\mu_x - \mu_y)^2} = \rho \times C_b.$$ In this formula, $\sigma_x$ and $\sigma_y$ are the standard deviations of $X$ and $Y$, respectively, showing the variability within each set of measurements.

Jan 17, 2024