In one of our studies using Qualtrics, we came across the problem of randomly assigning participants to different experimental conditions repeatedly.
The point was that we wanted everybody to experience a manipulation depending on condition, then have everybody fill in the same measures, and then present some more materials again depending on condition.
Randomizing the experimental conditions ONCE is easy, but how to do that repeatedly?
Our quite simple solution was to create embedded data fields that store the assignment to condition, and then branch according to that field.
To do this, in the survey flow you set up in the beginning a randomizer
Click survey flow and add a new element: Randomizer
Under this element, add the conditions you want to randomize by pressing add new element here: Embedded data.
On the embedded data element, type “condition” and the label of the condition (e.g. number) on the value field. Do this for every condition.
Go back to the randomizer and choose to “randomly present 1 of the following elements” and tick “evenly present elements“.
At this point, it should look like this (example with four conditions):
Below, add a new element: Branch
In branch, select “If” Embedded Data, type “condition” and select Is Equal To, and type the name/number of the condition
something like this:
Under the branch add a new element, that will be the block containing the desired stimulus for that condition
Do the same for all the experimental conditions.
it should look like this (again, example with four conditions):
In this example, the Blocks Entitativity and ManCheck are done for all participants in the same manner.
After that, you can then repeat the branching and do more condition-specific manipulations or measures.
If you have the problem that there is only very little change between your conditions, for instance a different label, there is alternative: Store the label itself in an embedded data field and insert it with Piped Text.
(written by Pedro Marques and Thomas)