The VARSTOCASES and CASESTOVARS commands

The below can also be performed using the [:FAQ/mixedR:RESTRUCTURE] command under the DATA menu in SPSS. For the example below we wish to stack columns x and y to make a single column called time. This is particularly useful for converting data from a format suitable for repeated measures to one suitable for multilevel modelling in SPSS. Notice we need to sort the cases before reformatting the data.

DATA LIST FREE / idno x y . 
BEGIN DATA 
001 34 56 
002 23 45 
003 39 41 
004 33 11 
005 87 57 
006 99 36 
END DATA. 

SORT CASES BY IDNO.
VARSTOCASES 
 /MAKE time FROM x y
 /INDEX = newfact "new var label" (time) 
 /KEEP = idno.

To do the reverse operation we need to use the CASESTOVARS command in conjunction with SORT CASES as below:

DATA LIST LIST/sub score.
BEGIN DATA                
1 34                    
1 56                    
2 23                    
2 45                    
3 39                    
3 41                    
4 33                   
4 11                    
5 87               
5 57
6 99
6 36    
END DATA.                 
LIST.                     

COMPUTE num=1.                       
IF sub = LAG(sub) num = LAG(num)+1.
LIST.  
                                                                   
SORT CASES BY sub num.             
CASESTOVARS                          
 /ID = sub                           
 /INDEX = num.                                      
LIST.