Does the Random Generator divide the participants equally?

Question

Hello!

I designed my questionnaire and am doing the pretest part, so soon ready to start, but a question came to my mind.
My questionnaire contains four conditions, which are randomized by a random generator, so every person is assigned to one question (and does not see the other 3).

But my question is: Does the random generator take count of the number of participants? As I would need 120 people (more or less 30 pro condition), can I trust that a proportional/equal number of people are assigned to each condition, even if I don't have a list with 120 emails at the beginning (since I will not send the link to everyone at the same time because I don't have 120 email addresses, but I hope to reach the target number within the time frame where the questionnaire is active). Or should I program/change some settings for that?

I hope my question is clear, thanks for the help

Answer 1

can I trust that a proportional/equal number of people are assigned to each condition

There are different settings available in the random generator how the randomization should work.

The default is to count the cases upon drawing. That means: If 120 people reach the page with the random generator, 30 will be sent to each of the 4 condition. If 20 drop-out in one of the conditions, that group will be smaller in the end.

The mechanism works like this: The random generator has a counter (visible in the random generator on the right), and it will take one of those codes that have the smallest count.

Another option is to tell the random generator no to count when the code is drawn, but when the questionnaire is finished (FINISHED=1). Sound nice, and work fine - but there are two drawbacks: First, that will create groups of different size when a large number of respondents starts at the same time. Because it has to draw before all have reached the end. And second, respondents leaving the questionnaire earlier (e.g., not answering an open-ended "any comments" before the last page) won't count.

There are also further mechanisms. Yet, I usually recommend the default setting.