There is no built-in option to randomly show 1 of X questions in LimeSurvey.
This article shows a practical workaround using an Equation question and relevance conditions to randomly select and display exactly 1 of X questions per participant. The approach works reliably across different LimeSurvey versions and survey types.
The Basic Idea: Randomly Show 1 of X Questions in LimeSurvey
LimeSurvey offers various randomization features. One common randomization use case is showing different versions of a question at a LimeSurvey survey. To do so, you need to randomly show 1 of the X question versions to the user. So the first step would be to generate a random number between 1-X. For this we can use the powerful LimeSurvey Expression Manager.
Generating a Random Value with a LimeSurvey Equation Question
The equation question type is listed at the “Mask questions” section. We will use it to store the result of the random function. So first step is to create an “equation” question with question code “randnumber”. At the question text you can add a simple note like “Hidden question for creating a random number”. On the right at the question settings at section “Logic” you can add this equation to generate a random number between 1 and 2:
{if(is_empty(randnumber.NAOK),rand(1,2),randnumber.NAOK)}
The whole code basically means that the system should first check if the randomnumber variable was already populated. If it is still empty, a random number between 1 and 2 is created. Else, the already created number is kept and no new random number gets created.
If you want to hide the question from the user, set “Always hide this question” to “yes” at the advanced question settings.
Using Relevance Conditions to Display the Selected Question
Now we have a question that will be filled with either 1 or 2, we can use conditions at following questions to show version A or version B of a question. For this you can use the LimeSurvey condition manager and set a condition based on a constant value of 1 or 2 for the equation question. Alternatively you can use the “relevance” field to define when a question should be shown. The appropriate relevance reads:
((randnumber.NAOK==1))
…and for the second question:
((randnumber.NAOK==2))
Don’t forget to check if you set up everything correctly by having a look at the survey logic file.
…and if this still sounds too tricky, we can set up the survey for you or provide LimeSurvey support on demand.