sum HH1 HH2 LN // HH1=cluster number, HH2=household number, LN=line number (child in household)
gen idnumber = string(HH1) + " " + string(HH2) + " " + string(LN)
gen id = string(HH1) + " " + string(HH2) // use this to merge with hh data below
save ch.dta, replace // this will save to current working directory

use "/Users/justinegosling/Desktop/Malawi_MICS5_Datasets/Malawi MICS 2013-14 SPSS Datasets/House hold.dta"
// 28479 observations, 177 variables
// this also has the same HH1 HH2 variables:
sum HH1 HH2
gen id = string(HH1) + " " + string(HH2) // to merge on household id with child data

merge 1:m id using "/Users/justinegosling/Desktop/Malawi_MICS5_Datasets/Malawi MICS 2013-14 SPSS Datasets/childrens .dta"

Can someone please tell me why after the above coding when I try to merge the data states response is: variable id not found r(111);

Many thanks