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How can I speed up gllamm?

Title   Speeding up gllamm
Author Minjeong Jeon, University of California, Berkeley
Date July 2012

There are two strategies to speed up gllamm: First, collapse your data and specify frequency weights. For instance, if you have several identical level-2 units, using level-2 weights makes gllamm enormously faster than without the weights. See FAQ on creating frequency weights for gllamm, and FAQ on specifying frequency weights in gllamm.

Second, use better starting values. For instance, you can use estimates obtained from a simpler model as starting values for your target model using the from() option. Starting values for the parameters that do not appear in the simple model are set to zero by default. By doing this, you can save iterations and consequently reduce the computation time in gllamm.

Examples and documentation

  • Description of from() option on p.25 and examples with the from() option on p.37, p.41, p.82, p.92, p.100 of Rabe-Hesketh, S., Skrondal, A. and Pickles, A. (2004). GLLAMM Manual. Free content U.C. Berkeley Division of Biostatistics Working Paper Series. Working Paper 160.
  • Examples with the from() option on p.17 and p.39 of glamm companion for Rabe-Hesketh, S. and Skrondal, A. (2012). Multilevel and Longitudinal Modeling Using Stata (3rd Edition). Volume I: Continuous Responses. College Station, TX: Stata Press.
  • Examples with the from() option on p.598, 609-613, and p.887 and in exercises 10.8 and 11.7 in the book Rabe-Hesketh, S. and Skrondal, A. (2012). Multilevel and Longitudinal Modeling Using Stata (Third Edition). Volume II: Categorical Responses, Counts, and Survival. College Station, TX: Stata Press.

References