"For Horizon, the state's largest health insurer, 80 percent of New Jersey's 27,000 doctors are in its network. Of the 5,500 that aren't, Horizon found about 200 of them bill certain services at 1,000 percent of what's allowed under the Medicare fee schedule ... The Newark-based insurer has identified another 2,000 doctors with charges equal to about 500 percent of what's allowed under those same guidelines."