Youden plots are used to analyze inter-laboratory data and compare both the within-laboratory variability and the between-laboratory variability.
Suppose that at each of several laboratories, a measurement is obtained for each of two products. The measurements for the first product are in C1, the measurements for the second product are in C2, and the laboratory identifier numbers are in C3. You want to create a Youden plot to compare the within-laboratory variability and the between-laboratory variability.