distractor analysis error

Elvire Alice · Post by **Elvire Alice** » Fri Oct 24, 2025 8:46 am

Hello,

My name is EA and I am working as a language test developer. I have recently taken my first steps in the world of test analysis and I am still learning about the wonderous world of Jamovi. We know that ideally a test should comprise of more than 10 items to do a proper analysis, but for now, this is what we have to work with. We have an issue with the distractor analysis of a particular test batch and even though the parallel test forms are equally comprised of 10 items, there haven't been any issues with the other analyses. We keep getting the 'breaks are not unique' error and although we tried to resolve the issue, we cannot find the problem. We have inserted the test takers' answers again in an excel file, changed it to csv, changed the language settings, etc. I am just a beginner so that is why I am reaching out to you. Maybe I have overlooked something? If you need extra info, please do ask. Thank you so much in advance for your time and effort.

seol · Post by **seol** » Fri Oct 24, 2025 10:50 pm

Hi EA

The newest version of snowIRT resolved the issue of 'breaks are not unique'.
please download the following version of snowIRT module in jamovi library.

Best Regards
Seol

Elvire Alice · Post by **Elvire Alice** » Fri Jan 16, 2026 10:43 am

Hi Seol,

Thank you for your reply. I have been out for a while, so I have missed your message, but I'm back and I'll try to do as you suggest.

Thank you very much!

Elvire Alice · Post by **Elvire Alice** » Fri Jan 16, 2026 10:47 am

Hi again,

I've installed the update - which is the 5.1.8 version, and I have tried again, but I still get the error 'breaks are not unique'. We only have three possible answers, A, B and C, might it have something to do with that?

Thank you for your help!

seol · Post by **seol** » Sat Jan 17, 2026 12:02 am

Hi
Yes, that is very likely the reason.

The error "breaks are not unique" is a common R issue that occurs when the data have only a few distinct response categories (such as A, B, C). In these cases, jamovi internally relies on R functions that automatically compute break points for plotting or categorization, and this process can fail when the number of unique values is very small. This behavior is common in multiple-choice or ordinal data and is not related to the jamovi version itself.

If you can send the .omv file in which the error occurs, I would be happy to take a look and see if there is anything else contributing to the issue.

Best
Seol

jamovi