Hi all, I am using R package 'ordinal' to fit a cumulative logit ordinal model with random effects. Does someone know 1) The optimization method used in estimating the parameters from the marginal likelihood? 2) In Adaptive Gauss-Hermite Quadrautre, let f() be the function to be intergrated. The second derivative of function f() with respect to the random effect needs to be calculated in order to center and scale the quadrature points. Is the second derivatie of f() derived to an exact form or approximation form, if the approximation form, what is the method used to approximate. Thanks, -Jiayi __ Jiayi Hou Department of Biostatistics School of Medicine Virginia Commonwealth University [[alternative HTML version deleted]]