HHS and NIH sometimes create “prize” or “challenge” competitions to announce a problem to the public, receive participants’ solutions to the problem, and then award prizes to the best solutions.
For a competition, typically, an agency selects winners after assessing work that has been completed; though for some complex, multi-phase challenges, an agency will select winners progressively as developmental stages are achieved. This differs from grants or contracts, where an agency instead receives research proposals, makes selections, and then pays awards incrementally as the work is done.
Challenges tend to have smaller sets of requirements than grants or contracts, specifically to allow space for participant creativity. All federal agencies’ challenges are indexed at Challenge.gov, which also provides a User Guide for Public Solvers and Case Studies.