Health and Human Services is huge and sprawling, encompassing many agencies with overlapping mandates. That's why the Office of Planning and Evaluation, housed within the secretary's office, is so key to coordinating policy. Moulds, 45, runs the department's in-house think tank, building models to understand the implications of policy choices and helping to coordinate policy design between the department's offices. With the administration acting to finalize regulations and implement the Affordable Care Act, it's a big job. Moulds came to health care by a circuitous route. The Sacramento, Calif., native was completing his Ph.D. in philosophy at the University of Illinois when he was struck with the desire to apply his skills more practically. That brought him to a fellowship program in the California Senate and got him hooked on policy. Before he joined the Obama administration in 2009, he spent several years as the head of the state's Office of Research, where he studied the policy implications of legislators' ideas and helped direct them toward the best approaches. (That included a health reform initiative that never came to fruition.) "What I do now really comes out of this interest in translating the world of ideas into the world of practice," he says. When he isn't doing that, he's home with his wife in Washington's U Street neighborhood, "playing defense" with their 18-month-old twin daughters.