Wizards of Qualtrics, please help: How do I evenly present items ONCE ACROSS different blocks?

Question

Hi everyone,

I'm having trouble with randomisation, and your help would be much appreciated:
I have a database of 100 images, along with 5 different measures. The study has 5 blocks. In each block, participants need to be randomly presented with 5 images from this 100 and then randomly presented with 1 of the 5 measures. This then needs to be repeated a further 4 times (so that by the end of the study participants have had all 5 measures, and looked at 5 groups of 5 images - that is, 25 different images in total randomly selected from the 100). Crucially, however, and this is the part I'm struggling with, I don't know how to tell qualtrics not to give the same images or measures twice *accross the different blocks*: e.g. to ensure that if an image or measure appears in block 1, say, it will not be selected to appear in blocks 2, 3, 4, or 5. Does anyone know how this can be done?

'Evenly Presenting' images and measures once won't seem to do it, as this will surely only do this within a block, and will reset when it comes to the next block.

Any help with this would be much appreciated. Thanks so much to you all in advance.

Warm and desperate wishes,

Ryan

Anonymous · Accepted Answer

Hello @RPD ,We can achieve this using JS.For Measures - Create 5 embedded  data in survey flow. Assuming measures are some text. Create an array with array element as measure text and shuffle this array using JS. Set first element of embedded data with first element of shuffled array, second with second and so on. Set these embedded data in the measure's position of each block. For Images - Create 100 embedded  data in survey flow. Create an array with array element as 100 image URL and shuffle this array using JS. Set first element of embedded data with first element of shuffled array, second with second and so on. ( We can also randomly pick the item for randomized/shuffled array for first, second....etc  ). Set these embedded data in the src attribute of image tag sequentially. Explanation: The array in both the cases are shuffled and array elements are assigned to embedded data. Since the araay is shuffled, every time the embedded variable are set with new measure or image.Please see below post as they have similar requirements as yours.1. https://www.qualtrics.com/community/discussion/3178/randomize-mp3-between-blocks2. https://www.qualtrics.com/community/discussion/comment/4825/Randomization

MsIreen · Answer

I would also be interested in this... Randomization with conditions is still a bit of a mystery for me..

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