Would someone help explain why the one method of using an array works as I would expect but the other method doesn't work as I would expect?   The only change I make to the code is to the array member declaration (colon placement).  The vol_: variables are all numeric and the other three vars are character.  Notice how "method two" affects the vol_I_0000 variable but doesn't appear to effect the other volume variables. Thanks for any help or insight! XXXXXXXX INPUT DATA                                                                                            vol_I_       Obs    store_id    quarter    year    vol_g_zz    vol_g_fp    vol_g_bd    vol_g_pl     0000                                                                                                           936     001500      Q109      2009         3         446          75          0         524        937     001500      Q209      2009         1         422          48          0         471        938     001500      Q309      2009         0         360          67          0         427        939     001500      Q409      2009         0         385          55          0         440        940     001500      Q110      2010         0         348          84          0         432     ARRAY METHOD 1 DATA share_one;                                                                                                           SET &cleaned_data(KEEP=store_id year quarter vol_g: vol_i: );           ARRAY share vol_g: vol_i:  ;                                                                           DO OVER share;                                                                                                        IF vol_i_0000 NE 0 THEN DO;                                                                                   share = (share / vol_i_0000);                                                                                 END;                                                                                                                                                                                                                        ELSE IF vol_i_0000 = 0 THEN DO;                                                                               share = 0;                                                                                                    END;                                                                                                  END;                                                                                                          RUN;       PRINT OF SHARE_ONE                                                                                          vol_I_ Obs    store_id    quarter    year    vol_g_zz    vol_g_fp    vol_g_bd      vol_g_pl     0000                                                                                                     1     001500      Q109      2009     0.00573     0.85115     0.14313             0       1      2     001500      Q209      2009     0.00212     0.89597     0.10191             0       1      3     001500      Q309      2009     0.00000     0.84309     0.15691             0       1      4     001500      Q409      2009     0.00000     0.87500     0.12500             0       1      5     001500      Q110      2010     0.00000     0.80556     0.19444             0       1   ARRAY METHOD 2 DATA share_two;                                                                                                           SET &cleaned_data(KEEP=store_id year quarter vol_g: vol_i: );           ARRAY share vol_: ;                                                                           DO OVER share;                                                                                                        IF vol_i_0000 NE 0 THEN DO;                                                                                   share = (share / vol_i_0000);                                                                                 END;                                                                                                                                                                                                                        ELSE IF vol_i_0000 = 0 THEN DO;                                                                               share = 0;                                                                                                    END;                                                                                                  END;                                                                                                          RUN;     PRINT OF SHARE_TWO                                                                                        vol_I_     Obs    store_id    quarter    year    vol_g_zz    vol_g_fp    vol_g_bd    vol_g_pl     0000                                                                                                           1     001500      Q109      2009         3         446          75          0          1          2     001500      Q209      2009         1         422          48          0          1          3     001500      Q309      2009         0         360          67          0          1          4     001500      Q409      2009         0         385          55          0          1          5     001500      Q110      2010         0         348          84          0          1       ... 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