Cronbach Coefficient Alpha

SAS's proc cor procedure produces two types of cronbach coefficient alpha: raw value and standardized value.

proc corr alpha data=dataname_here;
var  item1 item2 item3 item4 item5 item6 item7;
run;

The result table includes two values:

Cronbach Coefficient Alpha

Variables Alpha
--------------------------------
Raw 0.74
Standardized 0.75

Standardized version is based on standardized values of all variables included in the analysis.  If you standardize the variables yourself by creating z-score version of items and apply the same procedure, you will get the same value for both raw and standardized values.

proc standardize data=dataname_here out=dataname_here_B mean=0 std=1;
var  item1 item2 item3 item4 item5 item6 item7;
run;
proc corr alpha data=dataname_here_B;
var  item1 item2 item3 item4 item5 item6 item7;
run;

Cronbach Coefficient Alpha

Variables Alpha
--------------------------------
Raw 0.75
Standardized 0.75