Millisecond Forums

randomization in batch and experiment

https://www.millisecond.com/forums/Topic19896.aspx

By mongrel - 10/19/2016

Hi,

I am nearly done, thanks for all the help so far, Dave!

I have finished to program an batch consisting of 4 experiments.
I want a randomised assignment of subjects to two different experiments and solved that like this:

<batch>
/subjects = (1 of 2)
/file = "exp1.iqx"
/file = "exp2.iqx"
/file = "exp3.iqx"
/file = "exp4.iqx"
/ groupassignment = subjectnumber
</batch>
 
<batch>
/subjects = (2 of 2)
/file = "exp1.iqx"
/file = "exp2.iqx"
/file = "exp3.iqx"
/file = "exp4.iqx"
/ groupassignment = subjectnumber
</batch>

In exp1.iqx however, I want the participants also to be randomised to two different conditions, so that I in the end have four groups to compare:

1. batch1+exp1.1
2. batch1+exp1.2
3. batch2+exp.1.1
4. batch2+exp.1.2

The Exp.1 randomization looks like this:

    <expt conditionY2>
    / subjects = (1 of 2)
    / groupassignment = random
    / blocks = [1=instruct; 2=block1; 3=block2; 4=block3; 5=block.instructPost]
    </expt>
           
    <expt conditionY1>
    / subjects = (2 of 2)
    / groupassignment = random
    / blocks = [1=instruct; 2=block1; 3=block2; 4=block3; 5=block.instructPost]
    </expt>
**BETWEEN GROUPS**********************************************************************************************************
    <variables>
    / group = (1 of 2) (block2=Tool1Y1, block3=RecencyY2)
    / group = (2 of 2) (block2=Tool2Y2, block3=RecencyY1)
    </variables>
        
Now, I am afraid, I might have created only two comparison groups because the subject number seems to define not only which batch is chosen but also which condition of experiment 1...

Can you help me?

Thanks in advance!



By Dave - 10/20/2016

Make sure that both odd and even subject ids get into exp 1 by defining:

<batch>
/subjects = (1,2 of 4)
/file = "exp1.iqx"
/file = "exp2.iqx"
/file = "exp3.iqx"
/file = "exp4.iqx"
/ groupassignment = subjectnumber
</batch>
 
<batch>
/subjects = (3,4 of 4)
/file = "exp1.iqx"
/file = "exp2.iqx"
/file = "exp3.iqx"
/file = "exp4.iqx"
/ groupassignment = subjectnumber
</batch>