Millisecond Forums

batch file elements by subject number

https://forums.millisecond.com/Topic13280.aspx

By ktahaney - 5/13/2014

Hi,
I am trying to create a batch file in which there are 3 separate experiments where a participant completes a specific experiment based on subject number. Each subject will complete every experiment separately over the course of 3 weeks. The idea is that individuals will enter 0, 1, or 2 before their subject number such that 0001-0999 would be assigned to experiment 1 for week 1, 1001-1999 would be assigned to experiment 2 for week 2, etc. However, I am having trouble defining subject ranges in this way without getting an error. Is it possible to define subject ranges in such a way? Using the "1 of 2" language/odd numbered participants would not work as there are 3 experiments and each person needs to complete each one over time. Perhaps there is an alternative?
Thanks,
Kelli
By Dave - 5/13/2014

No, you cannot define ranges this way, that's not how condition assignment works -- condition assignment works by simple modulo arithmetic, i.e. computing mod(id,numberofconditions). What you can do is set up your batch elements like this

<batch>
/ file = "week1.iqx"
/ subjects = (1 of 3)
/ groupassignment = groupnumber
</batch>

<batch>
/ file = "week2.iqx"
/ subjects = (2 of 3)
/ groupassignment = groupnumber
</batch>

<batch>
/ file = "week3.iqx"
/ subjects = (3 of 3)
/ groupassignment = groupnumber
</batch>

A given participant's subjectnumber remains constant across the three experiments / three weeks. Her / his groupnumber changes -- 1 for the 1st exp, 2 for the 2nd exp, 3 for the 3rd.
By ktahaney - 5/14/2014

Thank you, Dave! One question, though. Is it possible to specify group number in this way when running the experiment via inquisit web scripts? It's not clear which, if any, group ID determination options would fit with this plan.
By Dave - 5/14/2014

Yes, perfectly possible in a web setting. Pass the id in via URL query parameter.