In its simplest case, this issue is about auto-fill of values based on another question's answer, but it is more than that. In LHC-Forms, selecting an answer to one question can cause another question's value to be filled in, but it can also cause another question's ValueSet (answer list) to be changed. For example, if you select "TYLENOL (Oral Pill) in the "Drug Name" field at https://rxterms.nlm.nih.gov/, the strength field is given the strength list for that drug name. This strength list is obtained from the value object for the Drug Name field. In LHC-Forms, the value of a field is not just the display text but also the answer code, and sometimes some extra data (like the strength list). To keep things simple, we would like to propose that any attribute of an item definition can be modified by the data from another item's answer. In the example above, item.option of the strength field would be assigned strength list data from the value object of the drug name field. For this capability, an item needs to specify:

1) The question its data is coming from

2) A path for where to get the data from the other question's value.

3) The attribute of the current item that should receive the data.