I am currently putting together an Inquisit experiment meant to be delivered by Inquisit's web platform.
I am trying to determine if we are able to do our eligibility screening within Inquisit or if we need to do that separately. (I think I am leaning towards doing it separately, just to avoid having people download the plug-in only to find out they are ineligible)
So I have a couple questions related to this, to help inform my decision.
1) Is it possible to record the source IP anywhere? It looks like computer.ipaddress is the IP address assigned to the local computer's NIC. That is not what I'm interested in. I am interested in the internet IP address that is the source of the web traffic to the server. I am very aware of all the reasons why that is not a good unique identifier (NAT, dynamic IPs, etc.) My question is only is that information available to me or not?
2) I have a script now that uses <include> statements and multiple <expt> blocks to randomly assign subjects to 4 different groups and it seems to work okay. There is some concern that we will end up with unequal group sizes using truly random assignment. I don' think we can get around that, it's either truly random (so you may end up with unequal group sizes, even though they should tend to roughly equal size), or you can do a round-robin assignment where group size will always be about equal, but you lose "randomness" outside of the generally random nature by which we expect participants to come to the study to begin with. I guess this isn't a question so much as an inquiry as to what others have done and any opinions they have about it.
I think right now I am leaning towards having a separate web survey somewhere that determines eligibility, and then doing group assignment outside of Inquisit, and providing eligible participants with a URL to the actual experiment, and the group number (or incorporating the group # into the URL to make it less error-prone) and having Inquisit just handle the experiment proper itself and not eligibility and group assignment.
John