Originally taken from here the macro b_to_w.sps stacks a defined number of columns on top of one other (representing within subject level responses) to form one column which can serve as a between subject factor response.
The between subjects factor is also created in the column called numb. Note: you can also use th restructure command to do this.
DATA LIST FREE /idno b1 x b2 b3. BEGIN DATA 1 3 4 7 1 1 6 5 8 2 1 3 4 7 3 1 3 3 6 8 2 1 2 5 10 2 2 3 6 10 2 2 4 5 9 2 2 3 6 11 END DATA. define w_to_b (id=!tokens(1) /nvars=!tokens(1) /vars=!cmdend). VECTOR b=!vars. LOOP numb=1 TO !nvars. COMPUTE newb=b(numb). XSAVE OUTFILE 'C:\test2.sav' /KEEP !id numb newb. END LOOP. EXE. GET FILE = 'C:\test2.sav'. LIST. !enddefine.
Let's give it a whirl:
w_to_b id=idno nvars=3 vars=b1 to b3.