0 votes
in SoSci Survey (English) by s219203 (310 points)

I am getting lost with all the randomization options and would appreciate anyone's help to simplify what I want to do.

I would like to present 90 images to participants using the selection sequence (one image per page with an associated question; same question for all images), divided in 4 blocks (25 images, 25, 20, 20). A single question is asked in-between the blocks. I need for the images to be randomly presented to participants (which are not divided in groups according to demographics or else; I want a true randomization), and for participants to see all of the 90 images.

Hence, I would need an option allowing for randomization/rotation of the images within a questionnaire for a participants, but also need the blocks to be linked to one another as I don't want the participant to see the same image twice.

Many thanks!

by SoSci Survey (301k points)
What effect do the blocks have? Do you want to keep the images from a block together? Or do you just want to shuffle all 90 images? You comment about "I want a true randomization" makes me suspicious in that aspect :)
by s219203 (310 points)
Thank you for your follow-up questions!

Ultimately, yes I want to shuffle all 90 images per participant. Since this is a lot for them to see at once, I need some little breaks so that participants maintain their attention. As such, in-between blocks, I ask bogus question (e.g., I was born on planet Earth: true or false), and then the images resume.

I previously had my survey on Qualtrics and I achieved this within their "survey flow" function. I used a "randomizer" to select 25 images to show amongst the 90 in the first block, then add a "display branching function" to each image in the second block. That way, the randomizer in the second block only picked images that weren't previously shown to the participant in block 1. Blocks 3 and 4 had the same display branching function so that in the end, the participant had seen the 90 images but in a random order ACROSS the 4 blocks.

1 Answer

0 votes
by SoSci Survey (301k points)

I want to shuffle all 90 images per participant. Since this is a lot for them to see at once, I need some little breaks so that participants maintain their attention.

Okay, so the blocks are just for presentation. That means you can shuffle all images, and then you want to present them in blocks.

Honestly, you should consider to show only 30 images per person to keep data quality up. But I am sure, you already did and have good reasons.

So, in SoSci Survey one option would be to create a random generator with all 90 images (for example their filenames) in it. And then you tell it to draw 90 codes per interview (or less, if you have mercy with your respondents).

So, if your random generator has the name RG01, this would be a simple code to display the forst 25 images drawn.

$images = array_values(valueList('RG01', null, 'label'));
$block = array_slice($images, 0, 25);
$image = loopPage($block);
html('<div><img src="'.$image.'"></div>');

Get started with that and then let's narrow down what you need.

by s219203 (310 points)
I've been away some time but am back working on my survey and I still have the same issues.

1. The "please wait" still shows. Is the update something I have to activate or is it applying automatically to all selection sequence questions now?

2. The progress bar still doesn't move when I show a block of images. I still haven't figured how and where to use the SoSciTools.progress.

3. As a clarification, I would like a participant to ultimately see the 4 "bogus items" during their survey, just to have them randomly selected between each block of images. Right now, I have the random generator on the page I first want to display a bogus question, followed by this PHP code:
      $questions = valueList('RG02', NULL, 'label');
      $identifier = loopPage($questions);
      question($identifier);
The subsequent pages have only the PHP code.
The first page do display a new, random bogus item each time, but it then skips the image blocks to only she the randomized bogus items and then end the survey.

As a reminder, the structure of my survey is as followed:
Page 1 = intro
Page 2 = bogus item 1
Page 3 = image block 1
Page 4 = bogus item 2
Page 5 = image block 2
Page 6 = bogus item 3
Page 7 = image block 3
Page 8 = bogus item 4
Page 9 = image block 4
Page 10 = end

Many thanks!!
by SoSci Survey (301k points)
> 1. The "please wait" still shows.

It should ... when the last subquestion was ansered and the browser loads the next page. The update hides the question text in that moment.

If you do not want the text to show up at all, just tell SoSci Survey that the text shall be &nbsp; (that's a non-breaking space).

> 2. The progress bar still doesn't move

Try to clear the browser cache, could be a caching issue. If not, please post a pretest link directly (!) to the page with the question, please.

> 3. As a clarification, I would like a participant to ultimately see the 4 "bogus items"

Okay, now the whole questions begins making sense :) Do I understand correctly, that you want to mix the blocks and bogus items and there shall not be a "visible" transition in between?
by s219203 (310 points)
edited by s219203
1. It's actually okay for this to show. Sorry about this. We can consider this issue solved.

2. Clearing the browser cache did help.

However, the % jumps a bit weird in-between pages of the questionnaire (e.g., between a bogus item and a block of pictures). This might be due to the use of blocks and selection sequence type of question, I guess. If we can't fix this, it is not an issue. I will run the questionnaire as is.

Another thing is that the bar only moves from 1% after each 5 pictures. I would like for it to move by whatever percentage it represents in the questionnaire after each picture shown. Is there a way we could do this? Again, we could also add a code to count the number of pictures presented so far and show some text for each image such as "Picture #X of 90".

If nothing can be done, I would be okay running the survey with the progress bar working as is.

3. I think you get the gist. The transition is not really the problem here but more so that either the bogus items or the picture blocks don't show with 2 random generators in the survey.

The main point is really about randomization. My pictures and the bogus items both need to be completely randomized. The pictures are working fine right now, but I can't seem to figure out how to randomize my bogus items. I would want for them not to be in the same order for each participant. So it could be items 1, 2, 3, 4 for the first participant, then 3, 4, 2, 1 for the next, then 2, 4, 3, 1, etc. I realize that the same combination (e.g., 1, 2, 3, 4) will come back for other participants, but that's okay. I just want it to be randomized every time an interview is started.

Thank you again!
by SoSci Survey (301k points)
SoSci Survey calculates the percentages based in page numbers. So if you have a very long page (or one that shows several sub-questions) and a very short page (only the bogus items), each will get the same share of the percentages.

You can use the option() function to adjust the percentage that is shown on a specific page. This, however, will not influence how far the bar moves on the page with the selection sequence.

In my opinion, the "clean" solution would be to get all items/subquestions into one question, and take care about proper rotation of the subquestions.

The other option would be to work a bit with JavaScript to tell the progress bar how far to proceed on the page. You can try this one als HTML code on the page:

<script type="text/javascript">
SoSciTools.progress.present(30, 20, 40);
</script>

This will tell the progress bar: The value on this page is 30%, the value on the previous page was 20%, and when we're done with the selection sequence, we shall arrive at 40%.

If you combine that with the PHP command on the next page...

option('progress', 40);

And that on the page after:

option('progress', 41);

Everything will run quite smooth. As I tried to explain, the issue is that the pages as so very different in their length.

> My pictures and the bogus items both need to be completely randomized.

One more argument to put them all together into ONE question and then take care about randomization.

The trick is this: You create two series of randomized numbers. You can do this via two random generators. One for the items (e.g., 1-60) and one for the bogs items (e.g. 61-64). As soon as you have these series in randomized order you use array_slice() and array_merge() to get this order:

* First 15 (e.g.) items from Item-Array
* First element from the Bogus-Array
* Second 15 (e.g.) items from Item-Array
* Second element from the Bogus-Array
etc.

May I suggest we create a new question on the rotation part? The coments down here are getting somewhat stuffed.
by s219203 (310 points)
I've created another thread: https://support.soscisurvey.de/?qa=42961/rotation-randomization-of-items-into-blocks

"Rotation/Randomization of items into blocks"

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