Fig. 1

Average MSE of item-to-domain correlation \( \rho \) for six items and unbiased experts. Average mean squared error (MSE) for item-to-domain correlation \( \rho \) using OBID (solid blue line) and ordinal CFA (dashed red line) when P = 6 (number of items) and experts are unbiased {\( {\rho}_0=\left(0.30,\;0.50,\;0.70,\;0.70,\;0.30,\;0.50\right)\Big\} \). The participant sample sizes are N = 50, 100, 200, and 500. The numbers of response categories are C = 2, 5, and 7, and the numbers of experts are K = 2, 3, 6, and 16. Note. OBID = Ordinal Bayesian Instrument Development; CFA = Confirmatory Factor Analysis