This tutorial demonstrates how to configure the Quota Node in the experiment tree. In this example, we want to branch participants based on whether they prefer cats or dogs, but we only want a certain number of participants in each group. This can be controlled via the Quota Node.
Firstly, we branch participants into two separate groups using their responses from the previous Questionnaire. You can find out how to do this in our Branching from a Questionnaire Tutorial.
Once we have branched participants into separate groups, we add two Quota Nodes to the experiment: one for each group of participants. For each of these Quota Nodes, we have created a new Quota: Quota 1 and Quota 2. Each Quota Node has two branches by default, an ACCEPT branch and a REJECT branch. If the quota has not been met, participants will be assigned to the ACCEPT branch and can continue with the rest of the experiment. If the Quota has been filled by other participants, they will be sent to the REJECT branch. In this case, the REJECT branch leads to the Reject Node.
Finally, we need to configure the Quota Nodes within the Recruitment Tab of the experiment. This is because the Quotas are directly tied to the Recruitment Target. To set up the Quotas, click on the Change Recruitment Target. Here, you can set how many participants you want to accept through each quota. To allow more participants in your experiment, you can increase the Quota size.