Forced Ranking Survey Question

For a subjective ranking, if an instructor is going to look at the learner's submission, you could use one text-input box and ask them to type their ranking in order (my first choice, my second choice, my third choice) that could be saved as a variable and sent via xAPI. 

If an instructor isn't going to be involved and/or you want to be able to report on the submissions in a more detailed way, your idea of separate type-in boxes could also be used, but as you note there is the challenge of preventing duplicate responses.

Another idea is to use a set of Menu elements (Insert tab >> Inputs >> Menus), one for each item in the list. This way the learner is choosing from a drop-down list offering the numeric rankings (1,2,3,4,5) to choose from. Each Menu can save to a distinct variable.

The menu approach, though, also doesn't prevent duplicate submissions without some extra help.

To do that, you could add a button to the page, Submit My Rankings. When clicked it fires an action/actions that check if any of the variable values match. If there is a match, you can show a message to the learner to make adjustments and Submit again. 

If there are no matches, the button can then send custom xAPI statements to send the value of each variable to the LRS, and those custom statements are what you’d report on. (The learner’s choices on each menu will still get sent automatically as xAPI statements as the learner makes each choice, so if there are two that match, you wouldn’t want to be reporting on these initial/automatic statements.)

This article explains creating custom xAPI statements:

Creating a custom xAPI statement >> https://dki.io/6dbeac68

Is there a correct ranking or is this more of a learner reflection activity where the ranking is subjective? 

Subjective--There is no right answer--we just need to know the order of how they rank the items. 

Amazing information and advice. I really appreciate the detailed response.