Is it possible to display or pull an answer from one question in a following question without using rosters? For example, the respondent gave their income in one question, and in some following questions I want to refer to the number that they provided. Is this possible?
yes, you can do that (although not for all question types). We call this text substitution. To do it, write the name of the variable wrapped in percentage signs in the text of the subsequent question. This is mentioned in the manual:
in section 3.3.1, 18.104.22.168, and other places.
Notably, you can apply this method to reveal the values of the hidden variables or of the computed variables.
Best, Sergiy Radyakin