I have a problem with an unexpected change in the value of a variable.

In my survey, I use an equation type question to define the variable "treatment" out of rand(1,2) within the first question group. However, two question groups later, "treatment" sometimes has a different value out of 1 or 2.
Is this normal? What can I do to change this? Ist there another way to randomly select participants into different treatments?

I have attached the logic file.

My LimeSurvey version is 2.50+160908. Unfortunately, I am not able to change it.

Thank you for all your help!

Have a look at this post about using an IF statement to ensure the rand() function only gets fired once - www.limesurvey.org/forum/can-i-do-this-w...randomisation#141077 .

This really seems to work! Thank you very much, Tony!