Rotation/Randomization of items into blocks

Question

This is a continuity of this discussion.

One more argument to put them all together into ONE question and then take care about randomization. ... create two series of randomized numbers ...use array_slice() and array_merge()...

This seems like a good alternative to my original design!
Could you please explain more.

Here are some questions/concerns that are coming to mind as of now:

• Right now, my picture items are under the same selection sequence question, and my bogus items are separate selection questions (under the same section). Do I understand that they should all be under the same selection sequence question?
• Would this mean the task is grouped under a single page in the questionnaire with a PHP code splitting the items into image blocks and bogus items on different visual pages for the participants?
• A potentially complexifying element is that the bogus items act as filter question; if someone answers incorrectly, their survey is ended. I would thus like to keep this filtering element.

Answer 1

A general condition to put all items and bogus items into one question is that there are no more than 99 of them. Yet, you should not reach that limit anyway, because respondents' attention will be lost on such a long, boring way, anyway.

Right now, my picture items are under the same selection sequence question, and my bogus items are separate selection questions (under the same section). Do I understand that they should all be under the same selection sequence question?

Yes, that would make things easier, especially the transition between bot item "types".

Would this mean the task is grouped under a single page in the questionnaire with a PHP code splitting the items into image blocks and bogus items on different visual pages for the participants?

Are we talking about a selection sequence? If yes, then all items would be on a single page in a single question, but would be presented one after another.

Using loopPage() would also allow different split variants for other types of questions.

A potentially complexifying element is that the bogus items act as filter question; if someone answers incorrectly, their survey is ended. I would thus like to keep this filtering element.

You will have to do this via JavaScript, if everything is on one page (Selection Sequence JavaScript). An alternative would be to present items + one bogus on one page, and work with loopToPage() to allow for a PHP filter after each such block. But let us postpone this filter stuff, an concentrate on the presentation, first.

Here is a good point to get started: Single Pages at Fixed Position - actually it's not such a big difference, if you rotate pages or items. The main difference is that you use question() instead of setPageOrder().

Comments

Moreover, there is the bogus items as filter questions. That is, if a participant select a specified answer, I want their interview to be done and for them to see a text element (a goodbye text, GT01).

You previously mentioned this would have to use Java, and copied this link: https://www.soscisurvey.de/help/doku.php/en:create:questions:selclick#respond_to_selection

I am quite unsure how to interpret this code. Any help appreciated!

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To add single items (i guess it may have the ID 99) you won't need an array_slice()

$allItems = array_merge(
  [99],
  array_slice($items, 0, 25),
  array_slice($bogus, 0, 1),
  array_slice($items, 25, 25),
  // ...

>  if a participant select a specified answer, I want their interview to be done and for them to see a text element

Let's start a new question in the online support for that - it's getting buzy down here.

What you need is such a JavaScript code on the page, and it may have to say something like this:

function onSelect(evt) {
  var info = evt.detail;
  if ((info.item == 91) && (info.value != 2)) {
    SoSciTools.submitPage();
  }
}

This is for item 91 for now, you'll have to add conditions for the other 3 bogus items as well.

For the error message, you may need a little PHP filter on the next page.

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The code works okay using [99], but it still has this glitch with the first picture showing before the "Let's start!" text...

I'll start a related question on the bogus as filters.

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> it still has this glitch with the first picture showing before the "Let's start!" text...

That could simply be the lag between loading the images and starting the question. One could build a workaround using JavaScript, but I have no ready-made fix for that.