Millisecond Forums

Hmmm then perhaps just a coincidence – albeit one with a very low probability – that everyone is going through on condition 1.. strange. 

I've looked at a bunch of your data files, and I don't see only condition 1. The other conditions appear to be present. What makes you conclude that everyone is going through on condition 1 and the others aren't run at all?

Those ones that go to condition 2  (212  and 207) are just me testing it (it seems to work for me). Without those runs, of the participants that have completed the study, 8 have been allocated to condition 1, 1 to condition 2 and none to condition 3. This seems very peculiar, especially since around 30 people have actually signed up to do the study. It makes me think the study is only working for those that are assigned condition 1. That is 1 in 3 participants who sign up.

I just did another test run. Was assigned group 2 by your php script. Parameter was properly passed on and into the script. Was administered condition 2 as expected.

Repeated same, was assigned parameter value of 3, was administered condition 3.

Testing under Windows, so as far as I can tell it isn't some weird Mac vs. PC issue either.

Is there a possibility that there's an error in your php script? I.e., does it perhaps generate a query parameter value of 1 more often than 2 or 3?

Thanks for running it for me Dave. I see your test. You were, after all, my only 99 year old ;) You are also now one of only 2 participants, other than me, to have been assigned any condition other than 1. This is out of now 20 participants. There is something definitely up with this. Maybe something is wrong with the php script, but it is simply set-up to select groups sequentially (as you saw when you tested it). This reminds me somewhat of the double slit experiment where as long as there is an observing instrument, it behaves as you would expect but as soon as I leave my participants to get on with it, everything gets stuck. Quantum physics non-withstanding, I am probably going to have to program the randomisation within Inquisit as having three separate links seems to be pretty unstable. I may have questions about that but I will post those, if they occur, to another thread. What I do wish was that there was a way to select groups randomly with no-replacement as you might the participant number. 

I got some more specific feedback from one of my participants: he's running windows 7 on an alienware 17 and said the following happened after he downloaded the plug-in:

"after clicking start, this pops up: Inquisit was unable to contact the server to verify that this script is licensed. The script will not be run."

does this shed any light on the matter? 

> "after clicking start, this pops up: Inquisit was unable to contact the server to verify that this script is licensed. The script will not > be run."

This means one of two things:

(1) TLS is disabled on the participant's box. To fix that, have her/him go to

Internet Options -> Advanced -> Security -> Check 'Use TLS 1.0'

(and any higher TLS versions). Previous protocol versions (SSLv2 and v3) are no longer supported by the server (they are insecure).

(2) A firewall or the like (either local or on the network perimeter) is blocking traffic between the Inquisit engine on the client and the server.

> What I do wish was that there was a way to select groups randomly with no-replacement as you might the participant number.                                

Hmm, that's actually the default option, so I'm not sure why you think this isn't possible.

Regarding your PHP redirection script: You have access to the server that hosts and runs the script. The server's logs should tell you exactly which IPs accessed it and the URL it redirected any given IP to (including the respective query parameter value). You can match those records with the logs available in your millisecond account. That should tell you which values your PHP script gave out and whether they correspond to the condition administered by Inquisit / the value of the group number. The server logs should also tell you whether the PHP script is giving out values as you intended it to or not.

Let me know what you find there.

Yeah the trouble is, the IT guy in our department set this php up so I don't have access at the mo.

> Hmm, that's actually the default option, so I'm not sure why you think this isn't possible. 

So am I right in thinking that if I just randomised the participant number and had the following for my batch file, would this achieve the randomisation I need? Would this split people into three roughly equal groups without the link?

Bare in mind the only difference in the experiment is the manipulationweb iqx.

<batch one>
/ subjects = (1 of 3)
/ groupassignment = groupnumber
/ file = "Consentformweb.iqx"
/ file = "manipulationweb_1.iqx"
/ file = "Questionsweb.iqx"
/ file = "Debriefweb.iqx"
</batch>

<batch two>
/ subjects = (2 of 3)
/ groupassignment = groupnumber
/ file = "Consentformweb.iqx"
/ file = "manipulationweb_2.iqx"
/ file = "Questionsweb.iqx"
/ file = "Debriefweb.iqx"
</batch>

<batch three>
/ subjects = (3 of 3)
/ groupassignment = groupnumber
/ file = "Consentformweb.iqx"
/ file = "manipulationweb_3.iqx"
/ file = "Questionsweb.iqx"
/ file = "Debriefweb.iqx"
</batch>

I don't see why you would even need three <batch> elements and three versions of manipulationweb.iqx. Why can't you just leave everything as is and just set your launch page to generate a random groupid instead of retrieving it from a query parameter?

I'm sure I'm missing something here, but I don't know what.