I am currently using the Laplace approximation to fit some geostatistical models for binomial data. Regarding parameters estimation I do not have any problem. I can easily implement the Laplace approximation and get my estimates.
But when it comes to obtain the standard errors I am puzzled about how I can derive the hessian of my objective function, hence the Fisher information. I tried to derive this analytically but it seems very laborious and tedious. Is there any reference about this or someone has a solution?