Sometimes there really are economies of scale. And the nation's health insurance exchanges may be a case in point. As rocky as the rollout of Healthcare.gov was, the federal exchange was relatively efficient in signing up enrollees. Each one cost an average of $647 in federal tax dollars, an analysis finds. It cost an average of $1,503 – well over twice as much – to sign up each person in the 15 exchanges run by individual states and Washington, D.C. The findings, released Wednesday, were drawn from federal enrollment and funding figures for the exchanges. The author is Jay Angoff, a former Missouri Insurance Commissioner and one-time director of the Health and Human Services office in charge of getting the health exchanges going.