How can I separate a treatment group and control group using random generator?

Question

Hi there,

I am currently stuck with random generator. I would like to have the questionnaire randomly distributed, and people in the Treatment Group should answer question VE07, and VE08 for those in the Control Group. But all other questions and procedures are exactly the same.

Here is what I did: on page 2,

First I created a random generator question, ID is RG01;
codes are:
1 = Treatment Group
2 = Control Group

Then, under this question, I inserted a PHP code:

if (value('RG01') == 1) {
question('VE07');
} else {
// You may omit the else part,
// nothing happens here
}

Lastly, both questions VE07 and VE08 are listed on below on the same page.

However, the result looks ridiculous, question VE07 appears twice, and I have no idea how to solve this, could you please help me with this problem?

Best,

Ji

Answer 1

Try this one, please

if (value('RG01') == 1) {
  question('VE07');
} else {
  question('VE08');
}

And then (that's the important part) make sure that you DO NOT have the questions VE07 and VE08 dragged into the questionnaire page. If you have already dragged them there, please remove them: Problem solution for filters (Top 3).