Millisecond Forums

Controlling number of participants per cell

https://forums.millisecond.com/Topic36789.aspx

By shareli@univ.haifa.ac.il - 12/18/2024

Hi
Say I have 10 conditions in my experiment which I run on the web. I wish to have 30 participants allocated to each condition. Conditions appear randomly. Is there a way to ensure that I get only 30 participants per condition and not more so that a condition stops being selected once it is full. Also, since participants may start the study but not complete it, I want to stop selecting the condition only when completed studies reached the number of participants set. Is there a way to do it? 
Thanks much
Shlomo 
By Dave - 12/18/2024

Hi
Say I have 10 conditions in my experiment which I run on the web. I wish to have 30 participants allocated to each condition. Conditions appear randomly. Is there a way to ensure that I get only 30 participants per condition and not more so that a condition stops being selected once it is full. Also, since participants may start the study but not complete it, I want to stop selecting the condition only when completed studies reached the number of participants set. Is there a way to do it? 
Thanks much
Shlomo 

The only way to do that is to (1) assign conditions by group ID, (2) pass in group ID via URL parameter, and then (3) give 30 participants the link for condition 1, another 30 participants the link for condition 2, etc.

You'll still have dropouts, so if, say, condition 7 is missing 3 participants in the end, you just recruit another 3 and give them the link for condition 7.
By shareli@univ.haifa.ac.il - 12/19/2024

Dave - 12/18/2024
Hi
Say I have 10 conditions in my experiment which I run on the web. I wish to have 30 participants allocated to each condition. Conditions appear randomly. Is there a way to ensure that I get only 30 participants per condition and not more so that a condition stops being selected once it is full. Also, since participants may start the study but not complete it, I want to stop selecting the condition only when completed studies reached the number of participants set. Is there a way to do it? 
Thanks much
Shlomo 

The only way to do that is to (1) assign conditions by group ID, (2) pass in group ID via URL parameter, and then (3) give 30 participants the link for condition 1, another 30 participants the link for condition 2, etc.

You'll still have dropouts, so if, say, condition 7 is missing 3 participants in the end, you just recruit another 3 and give them the link for condition 7.

Thanks much. This is a tedious solution so it is in essence no solution.