Using BMI as display logic for showing loop&merge fields that contain images | XM Community
Skip to main content

Hello,
I have quite the complicated question: I am trying to set up an experiment in which participants enter a loop with images shown only for a short amount of time. After each image they need to answer a question (question appears only after image). I have succeeded in setting this up.
Now here comes the crux: a participant's BMI determines the range of images that should be shown in their loop. I have approached this by setting up a separate a loop&merge field for a set of BMI intervals (every 0.5 BMI points) and piping each of these fields into separate pages (within the same block). Each page has display logic then has display logic which sets the interval of the BMI for that page to be shown.
I have calculated participants' BMI using embedded data. The embedded data that I ended up using for the display logic is a rounded version (BMIrounded) of participant's precise BMI (BMI2).
Without using BMI as a determinator for the images (so just using one field that includes all images) the experiment seems to work fine, but as soon as I add the multiple fields and display logic, the loop still runs (i still get the fixation cross first and the question that comes after each image, both are looped through the amount of times that images should appear), but no images are shown.
Any advice on how to get the images to appear? Maybe my code for BMI (rounded) in embedded data is wrong, or maybe something in the setup of my block? I've added screenshots below of my embedded data, parts of my block and the fields of loop&merge.
Beginning of the block:
Schermafbeelding 2021-03-27 om 18.54.06.pnganother part of the block:
Schermafbeelding 2021-03-27 om 18.47.38.png
embedded data in survey flow:
Schermafbeelding 2021-03-27 om 18.50.56.pngpart of the fields in loop&merge
Schermafbeelding 2021-03-27 om 18.50.31.png Thanks in advance!

It could be due to the multiple page breaks that are required before a question is displayed.
Since you are using display logic, try having all the images on the same page, ideally only one of them should be displayed.
Another strategy, that would simplify the setup would be have different L&M blocks for different BMIs. You won't have to worry about display logic in this case.


Leave a Reply