The position you are describing sounds great -- its paid, offers professional experience for someone interested in the field of research, the only question I would ask is if there is much interaction with you and other employees. If you added to the program a once a week coffee, where you or other experts in the office talked to the candidate for 30 minutes and offered context on how their work fit into a broader policy and research framework it would take the position to the next level and help you get superior candidates.