Millisecond Forums » Millisecond Forums » Inquisit 3 » Subject numbers & group assignment

RE: Subject numbers & group assignment

reyu7344 — Thu, 19 Jul 2012 01:59:07 GMT

Thanks Dave! Very helpful. I must applaud you for being so quick to reply as well.

RE: Subject numbers & group assignment

Dave — Thu, 19 Jul 2012 01:28:45 GMT

[quote]Guress they're not one-time though but no big issue.[/quote]

Yes, if you are talking about user-entered ids, they are *not* one-time.

[quote]Mathematics is not my forte, but I'm assuming both types of group assignment (subjectnumber or random) to result in pretty much equal distribution over the groups?[/quote]

Given a decent sample size, they should.

[quote]am I able to set numerical subject ids and still set /groupassignment to random?[/quote]

Yes.

RE: Subject numbers & group assignment

reyu7344 — Thu, 19 Jul 2012 01:16:02 GMT

[quote] Inquisit does not have any token system, so this is something you should ask the provider of said system. [/quote]

Sure. I've been reading this though, which talks about devising a system in which participants can specify their subject ID themselves. I guess this is what I mean by 'access token', just a number that I give to them that will be linked to their data when it's recorded, so I'm able to identify them. Guress they're not one-time though but no big issue.

[quote] If you supply a numerical subject id, the condition assignment will be based on the modulus of the respective id. If you don't supply numerical ids, you need to set /groupassignment to random. See e.g. https://www.millisecond.com/forums/Topic4148.aspx. [/quote]

Makes sense. Thanks for that. I'm happy to use either. Mathematics is not my forte, but I'm assuming both types of group assignment (subjectnumber or random) to result in pretty much equal distribution over the groups? Please correct me if I am wrong. And if I am wrong, am I able to set numerical subject ids and still set /groupassignment to random?

RE: Subject numbers & group assignment

Dave — Thu, 19 Jul 2012 00:17:44 GMT

[quote]My experiment is conducted online and I need to generate tokens that they then use as logins to access the experiment. This is so that I am able to identify which participants have completed the study so I can give them course credit. All the subject numbers need to be unique for this reason. I get that I can use a number of methods to generate subject numbers once I upload. First question: is there any way of making these tokens single use only to prevent them attempting the experiment again/quitting the experiment and restarting? If not, I'm assuming I could use date/time to identify the first time participants did the experiment. [/quote]

Inquisit does not have any token system, so this is something you should ask the provider of said system.

[quote]I also need to counterbalance the block order of three blocks of trials. I understand that I can use the /subjects = (1 of 3) attribute (2 of 3, 3 of 3) to do this[/quote]

If you supply a numerical subject id, the condition assignment will be based on the modulus of the respective id. If you don't supply numerical ids, you need to set /groupassignment to random. See e.g. https://www.millisecond.com/forums/Topic4148.aspx.

Regards,

~Dave

Subject numbers & group assignment

reyu7344 — Wed, 18 Jul 2012 20:04:13 GMT

Hi there,

My experiment is conducted online and I need to generate tokens that they then use as logins to access the experiment. This is so that I am able to identify which participants have completed the study so I can give them course credit. All the subject numbers need to be unique for this reason. I get that I can use a number of methods to generate subject numbers once I upload. First question: is there any way of making these tokens single use only to prevent them attempting the experiment again/quitting the experiment and restarting? If not, I'm assuming I could use date/time to identify the first time participants did the experiment.

I also need to counterbalance the block order of three blocks of trials. I understand that I can use the /subjects = (1 of 3) attribute (2 of 3, 3 of 3) to do this. I'm a bit confused as to how the roughly even assignment of subjects to these groups works, so am unsure of what else needs to included in the script for this to work. It's my understanding from http://ron.dotsch.org/inquisit-tutorial/ that it's linked to the subject numbers. Cheers,
Renee