{smcl} {* *! version 1.1.0 Tom Palmer 2sep2013}{...} {cmd:help reffadjust} {hline} {title:Title} {p 5}{bf:reffadjust} {hline 2} Introduction to random effects adjustment commands{p_end} {marker description}{...} {title:Description} {pstd}The {cmd:reffadjust} package provides postestimation commands to perform adjustment of random effects estimates. {pstd} The reffadjust commands are {p2colset 9 30 32 2}{...} {p2col :{helpb reffadjustsim}}simulating from the distribution of random effect variances and covariances{p_end} {p2col :{helpb reffadjust4nlcom}}regression coefficient formula to pass to {cmd:nlcom}{p_end} {p2colreset}{...} {pstd}Since multilevel models including random effects, such as those implemented in MLwiN (Rasbash et al 2009) and {cmd:mixed}/{cmd:xtmixed}, return estimates of the variances and covariances of the random effects and the corresponding variances and covariances of these estimates we can use these to estimate adjusted coefficients. {pstd}The approach is described in more detail in Macdonald-Wallis et al. (2012) and Palmer et al. (in press). {pstd}The commands run with estimates from {cmd:runmlwin} or chains from {cmd:runmlwin} by {cmd:mcmcsum} (Leckie and Charlton, 2011), {cmd:mixed}/{cmd:xtmixed}, {cmd:meqrlogit}/{cmd:xtmelogit}, and {cmd:meqrpoisson}/{cmd:xtmepoisson}. Note that in Stata 13 the following commands were renamed; {cmd:xtmixed} became {cmd:mixed}, {cmd:xtmelogit} became {cmd:meqrlogit}, and {cmd:xtmepoisson} became {cmd:meqrpoisson}. {marker references}{...} {title:References} {phang}Leckie G, Charlton C. 2011. {cmd:runmlwin}: Stata module for fitting multilevel models in the MLwiN software package. Centre for Multilevel Modelling, University of Bristol, UK. {browse "http://www.bristol.ac.uk/cmm/software/runmlwin/"} {phang}Macdonald-Wallis CM, Lawlor DA, Palmer TM, Tilling K. 2012. Multivariate multilevel spline models for parallel growth processes: application to weight and mean arterial pressure in pregnancy. Statistics in Medicine, 31, 3147-3164. {phang}Palmer TM, Macdonald-Wallis CM, Lawlor DA, Tilling K. Estimating adjusted associations between random effects from multilevel models: the reffadjust package. The Stata Journal. In press. {phang}Rasbash J, Charlton C, Browne WJ, Healy M, Cameron B. 2009. MLwiN version 2.1. Centre for Multilevel Modelling, University of Bristol, UK. {browse "http://www.bristol.ac.uk/cmm/software/mlwin"}. {marker authors}{...} {title:Authors} {phang}Tom Palmer, Division of Health Sciences, Warwick Medical School, University of Warwick, UK. {browse "mailto:t.m.palmer@warwick.ac.uk":t.m.palmer@warwick.ac.uk}.{p_end} {phang}Corrie Macdonald-Wallis, MRC and University of Bristol Integrative Epidemiology Unit, School of Social and Community Medicine, University of Bristol, UK. {browse "mailto:c.macdonald-wallis@bristol.ac.uk":c.macdonald-wallis@bristol.ac.uk}.{p_end} {marker acknowledgments}{...} {title:Acknowledgments} {pstd}We thank Chris Charlton and George Leckie (Centre for Multilevel Modelling, University of Bristol) for very helpful comments. {title:Also see} {psee} {space 2}Help: {helpb reffadjustsim}, {helpb reffadjust4nlcom}, {helpb runmlwin} (if installed), {helpb mcmcsum} (if installed), {helpb nlcom}, {helpb mixed}, {helpb xtmixed}, {helpb meqrlogit}, {helpb xtmelogit}, {helpb meqrpoisson}, {helpb xtmepoisson} {p_end}