/*Compare variable names and labels*/

use "C:\NHANES\DATA\alq.dta", clear
describe 
use "C:\NHANES\DATA\alq_b.dta", clear
describe 
use "C:\NHANES\DATA\demo.dta", clear
describe 
use "C:\NHANES\DATA\demo_b.dta", clear
describe 
use "C:\NHANES\DATA\bpx.dta", clear
describe 
use "C:\NHANES\DATA\bpx_b.dta", clear
describe 
use "C:\NHANES\DATA\mcq.dta", clear
describe 
use "C:\NHANES\DATA\mcq_b.dta", clear
describe 
use "C:\NHANES\DATA\bpq.dta", clear
describe 
use "C:\NHANES\DATA\bpq_b.dta", clear
describe 










/*directly append*/

//use C:\Nhanes\Data\demo_b
use C:\Nhanes\Data\demo, clear
keep seqn sddsrvyr ridstatr ridpreg sdmvpsu sdmvstra wtmec4yr riagendr ridageyr ridreth1 dmdeduc 
append using C:\Nhanes\Data\demo_b,keep(seqn sddsrvyr ridstatr ridpreg sdmvpsu sdmvstra wtmec4yr riagendr ridageyr ridreth1 dmdeduc) 
save C:\Nhanes\Data\demo_4yr, replace

//use "C:\Nhanes\Data\bpx_b"
use "C:\Nhanes\Data\bpx", clear
keep seqn bpxsy1 bpxsy2 bpxsy3 bpxsy4 bpxdi1 bpxdi2 bpxdi3 bpxdi4
append using C:\Nhanes\Data\bpx_b, keep(seqn bpxsy1 bpxsy2 bpxsy3 bpxsy4 bpxdi1 bpxdi2 bpxdi3 bpxdi4)
save "C:\Nhanes\Data\bpx_4yr", replace

//use "C:\Nhanes\Data\bpq_b"
use "C:\Nhanes\Data\bpq", clear
keep seqn bpq010 bpq020 bpq030 bpq050a bpq070 bpq080 bpq100d
append using C:\Nhanes\Data\bpq_b, keep(seqn bpq010 bpq020 bpq030 bpq050a bpq070 bpq080 bpq100d)
save "C:\Nhanes\Data\bpq_4yr", replace

//use "C:\Nhanes\Data\mcq_b" 
use "C:\Nhanes\Data\mcq", clear 
keep seqn mcq160b mcq160c mcq160d mcq160e mcq160f 
append using C:\Nhanes\Data\mcq_b, keep(seqn mcq160b mcq160c mcq160d mcq160e mcq160f) 
save "C:\Nhanes\Data\mcq_4yr", replace

//use "C:\Nhanes\Data\l13_b"
use "C:\Nhanes\Data\lab13", clear
keep seqn lbxtc 
append using C:\Nhanes\Data\l13_b, keep(seqn lbxtc)
save "C:\Nhanes\Data\lab13_4yr", replace







/*rename variable*/

use "C:\Nhanes\Data\alq_b" 
rename ald100 alq100
save "C:\Nhanes\Data\alq_b", replace

use "C:\Nhanes\Data\alq", clear 
append using C:\Nhanes\Data\alq_b
save "C:\Nhanes\Data\alq_4yr", replace








/* check contents*/
use "C:\NHANES\DATA\demo_4yr.dta", clear
describe 
use "C:\NHANES\DATA\bpx_4yr.dta", clear
describe 
use "C:\NHANES\DATA\bpq_4yr.dta", clear
describe 
use "C:\NHANES\DATA\mcq_4yr.dta", clear
describe 
use "C:\NHANES\DATA\lab13_4yr.dta", clear
describe 
use "C:\NHANES\DATA\alq_4yr.dta", clear
describe