Mix groups randomly and replace exactly three by different version

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2 years 11 months ago #115231 by whschreiber
whschreiber created the topic: Mix groups randomly and replace exactly three by different version
Dear list,

after many hours... I gave up.

What poses no problem at all is putting the groups in random order, thus I don't mention this further.

Task:
One can formulate the problem in 2 ways, each lead to the same solution:

1) You have 9 szenarios version A and B.
- the szenarios are to be presented in random order
- exactly 3 have to be version A, the other 6 version B
(here the szenarios would be in 2x9 question groups)

2) You have 9 szenarios
- the szenarios have to be presented in random order
- for exactly 3 szenarios a number of questions within the question group should be presented

One could also say that we have a long and short version for each szenario.

My intended solution was:

a) In an initial group I have to equation-questions, assigning 9 to SZENE and 3 to USED

b) within each Szenario (following way 2) I pick a random number between 0 and 1

c) in the relevance-equation I check if the random number is smaller or larger than USED/SZENE

d1) If larger the longer version applies

d2) if smaller or equal the shorter version applies *and* USED = USED-1

e) at the end of the block in an equation-question I set SZENE = SZENE-1

In theory that works fine but USED and SZENE seem not to be global but local to the group defined in (a). The names however are reserved, e.g. I cannot use them in (d2) or (e) as question code.

Furthermore I can even display them in further questions but not manipulate, e.g. decrement them.

Any ideas? I would greatly appreciate any suggestions.

[ of course I work with intval(), etc. I just didn't mention it to keep it less cluttered ]

Best, Walter.

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2 years 11 months ago - 2 years 11 months ago #115244 by tpartner
tpartner replied the topic: Mix groups randomly and replace exactly three by different version
So, if I understand correctly, you need to display 3 long versions and 6 short versions of the questions in random order.

I'm not sure you can get there with Expression Manager.

I would handle it using JavaScript and a hidden multiple-short-text question to control the display of the short/long versions.

1) Create 9 groups, each containing a long and short version of the same question (I suspect you have already done this). Display these in random order.

2) In a preceding group, add a multiple-short-text question (let's call it "control") with 9 sub-questions displayed in random order.

3) Add the following script to the "control" question. This will hide that question and populate its inputs. The first three inputs get a value of 1, the last six get a value of 2. (remember, the inputs are randomized, effectively giving them random values)
<script type="text/javascript" charset="utf-8">	
	$(document).ready(function() {
 
		// Identify this question
		var thisQuestion = $('#question{QID}');
 
		// Hide the question
		thisQuestion.hide();
 
		// Load the values
		if($('input.text:first', thisQuestion).val() == '') {
			$('input.text', thisQuestion).each(function(i) {
				if(i < 3) {
					$(this).val(1);
				}
				else {
					$(this).val(2);
				}
			});
		}
 
    });
</script>

4) Then you can use relevance based on the "control" question to show either the long or short question in each group. For example, something like this to for the long question in the first random group.
control_1 == '1'
And like this to for the short question in the first random group.
control_1 == '2'

Here's a working copy of the "control" question with that script in the source. (I have commented out the hide() function so you can see the values)

File Attachment:

File Name: limesurvey...5631.lsq
File Size:7 KB

Cheers,
Tony Partner
Solutions, code and workarounds presented in these forums are given without any warranty, implied or otherwise.
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Last Edit: 2 years 11 months ago by tpartner.
The following user(s) said Thank You: whschreiber

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