"An institute at another US university wants to pay a stipend to consult on test development items. The total amount would be less than $5000."
Because the stipend is less than $5,000 and from a U.S. institution, this does not need to be disclosed for conflict of interest review. This may, however, need to be disclosed for conflict of commitment review if it is an Outside Commitment, which can include fee-for-service activity and Research.
The Outside Commitment Decision Tree on our Disclosure Requirements webpage are available to assist individuals in determining what needs to be disclosed. Individuals can also contact OROI at coi@arizona.edu.