The groupassignment attribute determines how participants are assigned to between-subject conditions.
assignment |
One of the following values:
|
Between-subject groups can be defined using the expt or batch elements. Participants can be assigned to between-subjects groups based on the numeric subject id entered when launching the script, or by random assignment. This attribute specifies which method to use. By default, the subject id is used.
The following randomly assigns participants into one of 2 treatment conditions:
<expt conditionA>
/ subjects = (1 of 2)
/ groupassignment = random
/ blocks = [1=practice; 2=treatmentA; 3=test]
</expt>
<expt conditionB>
/ subjects = (2 of 2)
/ groupassignment = random
/ blocks = [1=practice; 2=treatmentB; 3=test]
</expt>