cd "C:\Users\chkim\The University of Kansas\OneDrive - The University of Kansas\Lectures\Soc910_AdvStat\examples"

use soc910_data_5_ind2_REM.dta, clear

keep if year>=1983

gen time = year-1983

* ---
* RCM: without other independent variables except time variable. 
* ---

* RCM with two-level random intercept
mixed lnwage time || ind: 

* RCM with two-level random intercept & slope
mixed lnwage time || ind: time

* RCM with two-level random intercept & slope
mixed lnwage time || ind: time, covariance(unstructured)


* ---
* RCM: with other independent variables to account for the random effects
* ---

* RCM with two-level random intercept: covariates only for intercept
mixed lnwage time union part || ind: 

* RCM with two-level random intercept & slope: covariates only for intercept
mixed lnwage time union part || ind: time

* RCM with two-level random intercept: covariates only for intercept
mixed lnwage time union part || ind: time, covariance(unstructured)

* RCM with two-level random intercept: covariates only for both intercept and slope
mixed lnwage time union part c.time##c.union c.time##c.part || ind: time, covariance(unstructured)


* ---
* REM vs. RCM-random intercept
* ---

xtset ind time

* REM
xtreg lnwage time union part, re mle

* RCM with two-level random intercept
mixed lnwage time union part || ind: 


* ---
* Hybrid Model 
* ---

egen mtime  = mean(time), by(ind)
egen munion = mean(union), by(ind)
egen mpart  = mean(part), by(ind)

gen ctime  = time - mtime
gen cunion = union - munion
gen cpart  = part  - mpart

reg lnwage ctime cunion cpart mtime munion mpart 

* ---
* Hybrid Model 
* ---
gen     t0wage1   = 0
replace t0wage1   = lnwage if year==1983

gen     t0union1 = 0
replace t0union1 = union if year==1983

gen     t0part1  = 0
replace t0part1  = part  if year==1983

egen t0wage  = max(t0wage), by(ind)
egen t0union = max(t0union1), by(ind)
egen t0part  = max(t0part1), by(ind)

gen clnwaget0 = lnwage - t0wage
gen cuniont0 = union - t0union
gen cpartt0  = part  - t0part

reg clnwaget0 time cuniont0 cpartt0
reg t0wage t0union t0part