****  Stata do file for meta analysis of teacher expectancy data ************

/*

See http://www.gllamm.org/bayes.html

Reference:
Chung, Y., Rabe-Hesketh, S. and Choi, I.-H. (2013). Avoiding zero between-study 
variance estimates in random-effects meta-analysis. Statistics in Medicine 32, 
4071-4089.

*/

* Install software (if needed)
ssc install gllamm, replace  
* download init_prior and calc_prior from http://www.gllamm.org/bayes.html
ssc install metaan, replace
ssc install metareg, replace

* load data from "Multilevel and Longitudinal Modeling Using Stata"
use http://www.stata-press.com/data/mlmus3/expectancy, clear

*** Meta-analysis, no covariates

* ML
metaan est se, ml

* REML
metaan est se, reml
metareg est, wsse(se) reml

* BM
eq het: se
constr def 1 [s1]se=1
gllamm est, i(study) s(het) nats constr(1) adapt prior(gamma, scale(10000) shape(2))

* DL
metaan est se, dl

*** Meta-regression
* mean-center weeks
qui summ weeks
generate cweeks = weeks - r(mean)

* ML or REML
metareg est cweeks, wsse(se) reml

* BM
eq het: se
constr def 1 [s1]se=1
gllamm est cweeks, i(study) s(het) nats constr(1) adapt prior(gamma, scale(10000) shape(2))