“…The non-journal articles 9,11,19,23,27 were mainly reports on either the cost or benefit of the intervention. Geographically, all studies were from the U.S., with five 1,2,11,21,22 from the Northwest, six 16,19,23,25–27 from the Northeast, two 17,18 from the Midwest, two 9,10 from the Southeast, and seven 12–15,20,24,28 covering the whole U.S. Fifteen 1,11–16,18–22,24,26,28 of the 22 papers provided cost information, and ten 2,9–11,17–19,23,25,27 provided benefit information. Three studies 11,18,19 provided both the cost and benefit information.…”