version 15

use https://www3.nd.edu/~rwilliam/statafiles/mdcoding, clear
fre var1
sum var1

mvdecode var1, mv(97=.a\ 98 = .b\ 99=.c)
fre var1
sum var1

label define agreement 97 "" 98 "" 99 "", modify
label define agreement .a "Don't Know" .b "Refused" .c "Not Applicable", add
fre var1

* Here are variations that might be appropriate in other situations
* For now, they are commented out

* mvdecode var1-var20, mv(97=.a\ 98 = .b\ 99=.c) 
* Use when var1-var20 are consecutive and coded the same

* mvdecode _all, mv(97=.a\ 98 = .b\ 99=.c) 
* Use when all variables have the same MD codes

* mvdecode var1, mv(97 98 99)  
* All MD gets assigned to ., the system missing value