Hi TomG, I think I'm having the same issue as Maddy.
We have a matrix where respondents list the foods they ate for a meal, then rate how much they like each food. They can list and rate up to 10 items (rows), and the rating for each item is a Likert scale (across columns). We'd like to force response Likert rating but only for rows where they actually entered something to rate. If you list 5 things, then force response (rating) for those 5 things. The global question-wide Force Response is no good because we don't want to force respondents to list 10 things if they don't have 10 things to rate. But we do want to ensure they rate everything they do list. Any insights/suggestions on if/how Custom Validation could enable this?
Any advice would be most appreciated!
Thanks,

Behavioral Health & Performance Laboratory
NASA Johnson Space Center

NASA_BHP_Lab,
As I just told someone else, it is best to avoid "allow text" on matrix statements. It results in a confusing respondent experience and is difficult to validate. The result is messy data.
You would be better off breaking into two questions:

1. A text form asking them what food they ate


2. A likert matrix where you carryover the entered text from the text form as the statements

Thanks Tom! We agree, that's actually the first thing we did. However, our colleague leading the project really wants the entries and ratings on one form on one page. Sorry didn't clarify that in our initial statement.
Interestingly it looks like the Custom Validation has Pass rules, but no Fail rules. I can require Pass = row 1 text entry not empty and rating 1 not empty + row 2 text entry not empty and rating 2 not empty, etc., but then it adds up to just Force Response for the whole thing. We only want to force ratings when text entry is not empty. Trying to figure out if/how Fail = rating 1 is empty when row 1 text entry is not empty + rating 2 is empty when row 2 text entry is not empty, etc. Certainly not elegant, and not even sure if it's do-able!

TomG and as clunky as it is on our end, there are advantages for the respondents. Cognitively it's a little more "ergonomic" as it's more like a paper/pencil form. If they forget something they can add as they go. If they're bound by the list they provide on page 1, then forget something as they're going through the ratings on page 2, I'd be concerned about using the Back button to add something on page 1 then losing/re-doing the ratings on page 2.

Okay, I think I got it.
Custom Validation, pass =
If Entry 1 not empty and Rating 1 not empty;
Add Another Logic Set "And If" Entry 2 not empty and Rating 2 not empty;
Add Another Logic Set "And If" Entry 3 not empty and Rating 3 not empty,
etc. through 10.

Thanks again for the advice!

NASA_BHP_Lab,
That won't allow for empty rows. I think it should be:
If Entry 1 not empty and Rating 1 not empty or Entry 1 empty and Rating 1 empty
Add Another Logic Set "And If" Entry 2 ...etc...

Hot dang, I think you got it, thanks TomG!

Your Wizard rating is well-deserved! Thanks again for your help and contributions to human space exploration, best wishes from NASA.