How to set default values in cascading select_multiple questions in KoboToolbox when the parent choice changes?

User Support Form Building
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1

Hi everyone,

I am working on a KoboToolbox form where I have a cascading select setup:

  • Parent question → center (select_one).

  • Child question → students (select_multiple) filtered by center. (cascading select)

Each center has its own list of students (s1…s104), and I want the child select_multiple question to auto-select a default set of students depending on which center is chosen.

For example:

centerA      →  s1 s2 s3 s4 s5 s6 s7 s8
centerB      →  s9 s10 s11 s12 s13 s14 s15 s16 s17 s18
centerC      →  s19 s20 s21 s22 s23 s24 s25 s26 s27 s28
centerD      →  s29 s30 s31 s32 s33 s34 s35 s36
centerE      →  s37 s38 s39 s40 s41 s42 s43 s44 s45 s46
centerF      →  s47 s48 s49 s50 s51 s52 s53 s54 s55 s56
centerG      →  s57 s58 s59 s60 s61 s62 s63 s64 s65 s66
centerH      →  s67 s68 s69 s70 s71 s72 s73 s74
centerI      →  s75 s76 s77 s78 s79 s80 s81 s82 s83 s84
centerJ      →  s85 s86 s87 s88 s89 s90 s91 s92 s93 s94
centerK      →  s95 s96 s97 s98 s99 s100 s101 s102 s103 s104

What I’ve tried so far:

  1. Using the default column → I can set defaults for the first load, but when the parent (center) changes, the defaults for the child (students) are cleared.

The problem I need solved:

  • When I select a parent (center), I want the child (students) to automatically fill with its corresponding default set of student IDs.

  • If I switch to another parent, the child should clear and refill with the new defaults (not remain empty).

  • This is especially important because the child question is select_multiple, so defaults need to be space-separated values (like s1 s2 s3).

Questions for the community:

1. Is it possible in Kobo/ODK to dynamically reset defaults for a select_multiple child when the parent changes?
2. Could I restructure the cascading setup (e.g., separate child questions for each parent and merge them later) to make this work more reliably?

Notes:

  • I’m okay with uploading an XLSForm (Excel) instead of using only the online form builder.

  • I need this working on KoboCollect/ODK Collect, and Kobo web (Enketo).

:folded_hands: Any detailed guidance, example XLSForm, or workaround would be hugely appreciated!

2

test_form.xlsx (17.0 KB)
Please test this sample form i created.

It will autoselect the answers on the select multiple based on the cascading question controled by the previous question. I hope it is what you want

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3

Thank you @pruzige this is exactly what i was looking for, so thankful to you!

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