# randomly assign participants to groups

4 years 3 months ago #94040
jvandernoll created the topic: randomly assign participants to groups
Hi,
I try to create something that will assign participants randomly to one of 4 groups, but I don't get it to work.

I work with LS 1.91, so I cannot add "question type equation". I have found some solutions, but I run into problems, so I think I make a mistake somewhere.

The following script I adjusted from another forum post (which can be found here www.limesurvey.org/en/forum/can-i-do-thi...-the-others?start=10 )

<script type="text/javascript">
<!--
{
// Find a random number between 1 and 4
var randNumber = Math.floor(Math.random()*3 + 1);
checkconditions(randNumber,'96682X129523X1961293','text');
})
//-->
</script>

where 96682 is Survey ID, 129523 is Group ID, 1961293 is Question ID)

In the next question group I created 4 questions, and depending on the random "answer" participants would get one of the 4 questions (by adding the condition "answer to 'random' question equals 1" --> question 1; "...equals 2" --> question 2, etc.). This seems to work.

When I try to hide this question, however, it does no longer work (the question is hidden, but the questions following this question are not shown either).

Also, if I have 4 groups, is the "Math.floor(Math.random()*3 + 1)" correct, or should it be "Math.floor(Math.random()*4 + 1)" (as is shown in the link below). And are the random numbers obtained than 1 2 3 and 4 or 0 1 2 and 3? I have tested the above solution a number of times, but only got 1 2 or 3 as a response. Not sure if that is just coincidence, or that I actually only create those 3 numbers.

This is another solution that I found, but it did not work for me:
docs.limesurvey.org/tiki-index.php?page=...rol_survey_behaviour

I hope someone can help!
Many thanks in advance!

4 years 3 months ago #94058
DenisChenu replied the topic: randomly assign participants to groups
Hello,

With 2.0 (or 1.92), you can use directly:
{rand(1,4)} in an equation question type.

Denis

Assistance on LimeSurvey forum and LimeSurvey core development are on my free time.
I'm not a LimeSurvey GmbH member, professional service on demand (or search sondages pro).
An error happen ? Before make a new topic : remind the Debug mode .

4 years 3 months ago #94060
jvandernoll replied the topic: randomly assign participants to groups
Thanks Denis,
Unfortunately, I work (via university server) with version 1.91, and don't have that option.
Any thoughts on how to solve this in 1.91?

Jolanda

4 years 3 months ago #94079 by tpartner
tpartner replied the topic: randomly assign participants to groups

When I try to hide this question, however, it does no longer work...

You cannot hide the question with the advanced question setting, You need to hide it with JavaScript:
`\$('#question96682X129523X1961293').hide();`
or with CSS
`#question96682X129523X1961293 { display: none; }`

Also, if I have 4 groups, is the "Math.floor(Math.random()*3 + 1)" correct, or should it be "Math.floor(Math.random()*4 + 1)"...

To get a random number between 1 and 4, use
`Math.floor(Math.random()*4)+1`

Cheers,
Tony Partner
Solutions, code and workarounds presented in these forums are given without any warranty, implied or otherwise.

4 years 3 months ago - 4 years 3 months ago #94081
jvandernoll replied the topic: randomly assign participants to groups
Thanks Tony!
I included the code for hiding the question in my javascript source, but it keeps showing the question...? Do you see the mistake in the code?

The source code that I have now is:
```<script type="text/javascript">
<!--
{
// Find a random number between 1 and 4
var randNumber = Math.floor(Math.random()*4 + 1);
checkconditions(randNumber,'96682X129523X1961293','text');
\$('#question96682X129523X1961293').hide();
})
//-->
</script>```

Thanks!
Jolanda.
Last Edit: 4 years 3 months ago by DenisChenu. Reason: [code type=javascript]

4 years 3 months ago #94086
DenisChenu replied the topic: randomly assign participants to groups
Thinks it's \$('#question96682').hide();

Assistance on LimeSurvey forum and LimeSurvey core development are on my free time.
I'm not a LimeSurvey GmbH member, professional service on demand (or search sondages pro).
An error happen ? Before make a new topic : remind the Debug mode .

4 years 3 months ago #94088
jvandernoll replied the topic: randomly assign participants to groups
Yes! That works, great!!
It still shows the page of the question, but if I add this question to another group, people won't notice.

Thanks!

4 years 3 months ago #94089 by tpartner
tpartner replied the topic: randomly assign participants to groups
Oops, sorry, moving too fast...

I think it should be :
`\$('#question1961293').hide();`

Or CSS:
`#question1961293 { display: none; }`

(Assuming the question ID is 1961293)

Cheers,
Tony Partner
Solutions, code and workarounds presented in these forums are given without any warranty, implied or otherwise.
The following user(s) said Thank You: DenisChenu, jvandernoll

3 years 8 months ago #100605
jvandernoll replied the topic: randomly assign participants to groups
Hi again,
following my earlier question - Now try to do the same with three conditional groups. I adjusted the code I used before (see below) to this:

<script type="text/javascript">
<!--
{
// Find a random number between 1 and 3
var randNumber = Math.floor(Math.random()*3 + 1);
checkconditions(randNumber,'96682X129523X1961293','text');
\$('#question96682X129523X1961293').hide();
})
//-->
</script>

but this does not work. Can you spot the mistake?

Many thanks!

3 years 7 months ago #101344 by cecilia
cecilia replied the topic: randomly assign participants to groups
Please, could you send me a copy of a survey applying the discussed function? I have access to LS 1.91+ from my University. I have changed the js template but I cannot use the question with the random number in conditional format. Thanks!

3 years 7 months ago #101488
jvandernoll replied the topic: randomly assign participants to groups
Hi Cecilia,
If you go to your question, you should include the code below in your source code (click source)
- This is for 4 conditions;
- you have to adjust the SurveyIdXGroupIdXQuestionId to correspond with your own Id-numbers (leave the X between the Id-numbers);
- and the last line \$('#question1979503').hide(); is to hide the question with question Id number 1979503 -- you need to adjust this too to correspond with your question ID

Hope this helps!

Here's the code:

<script type="text/javascript">
<!--
{
// Find a random number between 1 and 4
var randNumber = Math.floor(Math.random()*4 + 1);