Millisecond Forums

Participant subject number and group number error

https://forums.millisecond.com/Topic29529.aspx

By KatrinaMcDonough - 8/4/2020

Hello, 

I have a study with two groups, and within those two groups there are two versions depending on subject number (odd and even).
So in total there are 4 versions of the task:
Group 1, Even subject number
Group 1, Odd subject number
Group 2, Even subject number
Group 2, Odd subject number
I have set the subject ID to be sequential and the group number to be sequential and I have set the number of groups to 2.
I have launched the experiment myself, in a new browser each time, and the same task version being shown each time. The subject number is increasing by 2 each time (and so the subject ID is always odd), and the group number is always group number 2.
How can I fix this please?
Study link: https://mili2nd.eu/6dub
Thanks
By Dave - 8/4/2020

KatrinaMcDonough - 8/4/2020
Hello, 

I have a study with two groups, and within those two groups there are two versions depending on subject number (odd and even).
So in total there are 4 versions of the task:
Group 1, Even subject number
Group 1, Odd subject number
Group 2, Even subject number
Group 2, Odd subject number
I have set the subject ID to be sequential and the group number to be sequential and I have set the number of groups to 2.
I have launched the experiment myself, in a new browser each time, and the same task version being shown each time. The subject number is increasing by 2 each time (and so the subject ID is always odd), and the group number is always group number 2.
How can I fix this please?
Study link: https://mili2nd.eu/6dub
Thanks

There is nothing wrong with the setup, subject ids as well as group ids vary between odd and even just fine. You have some additional refresh in your testing setup that causes the increase by two. Do the following:
- Visit the start page.
- Launch.
- Go through the experiment or abort it.
- Launch again (no need to refresh the page or open it in a new browser).

Review the numbers.

By KatrinaMcDonough - 8/5/2020

Dave - 8/4/2020
KatrinaMcDonough - 8/4/2020
Hello, 

I have a study with two groups, and within those two groups there are two versions depending on subject number (odd and even).
So in total there are 4 versions of the task:
Group 1, Even subject number
Group 1, Odd subject number
Group 2, Even subject number
Group 2, Odd subject number
I have set the subject ID to be sequential and the group number to be sequential and I have set the number of groups to 2.
I have launched the experiment myself, in a new browser each time, and the same task version being shown each time. The subject number is increasing by 2 each time (and so the subject ID is always odd), and the group number is always group number 2.
How can I fix this please?
Study link: https://mili2nd.eu/6dub
Thanks

There is nothing wrong with the setup, subject ids as well as group ids vary between odd and even just fine. You have some additional refresh in your testing setup that causes the increase by two. Do the following:
- Visit the start page.
- Launch.
- Go through the experiment or abort it.
- Launch again (no need to refresh the page or open it in a new browser).

Review the numbers.


Thanks, Dave. I realise now what I was doing wrong. I also realised that by having both the subject number and group number sequential, group 1 will always have odd numbered participants and group 2 will always be even, so the two other versions would never show. I have now changed the group number to be randomised. Thanks for your help.