Does anyone know how to do a generalized estimating equation using Poisson log linear? Know a reference or a step-by-step tutorial? I'm having a hard time figuring out how to do this in SPSS and how to interpret the output. I still keep on getting errors such as "The Hessian matrix is singular. Some convergence criteria are not satisfied." and "The maximum number of iterations was reached but convergence was not achieved" even after following the information in the IBM SPSS website. I will appreciate any guidance. Thank you!