In 2017, the online professional network LinkedIn hosted a LinkedIn Economic Graph Challenge. Any U.S. resident over the age of eighteen could submit a proposal to LinkedIn requesting use of its data. After assessing proposals for novelty, impact, and feasibility, LinkedIn awarded winning proposals a $25,000 research prize. Participants had six months to complete their research. Winners of the challenge were only given datasets relevant for the purposes of the proposed research. The data is made available in a separate, secure “sandbox” environment on the company's hardware - this means the data is isolated from LinkedIn's active repository.