How to get an even participant distribution with 2x2 between subject design? | XM Community
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How to get an even participant distribution with 2x2 between subject design?

  • 6 April 2021
  • 1 reply
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As this is my first time using Qualtrics, I have run into a problem I hope someone can help me with. For my research, I will be using a 2x2 between subject design. At the beginning of my survey partcipants will be evenly divided between condition A and B. They will first participate in different questions, but then continue with another block of the same questions. After that, all participants will be evenly divided again between condition 1 and 2, where half of the participants will read a certain paragraph, and the others will not see this paragraph at all. Therefore, I will have 4 conditions: A.1, A.2, B.1, and B.2.
I know I can use the randomizer tool to evenly divide between A and B at the beginning, but I am wondering that if use the randomizer tool again later on in the survey for 1 and 2, will I get even distribution between all 4 conditions? If I understand correctly, the whole group will get evenly divided again, and the previous division will not be taken into account.
The only solution I have come up with so far is making 4 seperate blocks, and then randomizing those 4 evenly. I am however a little concerned that this will somehow mess up my output from the survey. It might be better to create 2 blocks for A and B, and then randomize evenly, and later in the survey randomize 1 block which half of the participants will see, and the others will not. I do however not know how to do that while avoiding uneven distribution of the participants.

I hope someone can understand my questions and help me out, it would be a great help!


1 reply

Userlevel 7
Badge +19

I'm not sure if it would evenly distribute it doing it all in one project... you can build it and generate some test responses to see if it works out like that! I should imagine if it truly is totally random, it should work itself out that way anyway.
If it doesn't- I would create 3 projects.
The first survey moves you to group A or B. Then automatically re-direct users upon completion to a new project. From A to "Project A Follow-Up" to get them into 1 or 2. From group B to "Project B Follow-Up" to get them into 1 or 2.

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