Overconsumption of healthcare services is the primary driver of escalating healthcare spending. But what contributes to overconsumption? The third-party payment system of employer sponsored insurance is the single biggest factor, but defensive medicine ── where a physician orders unnecessary tests or prescribes unnecessary treatments to limit his or her own malpractice liability ── plays a significant role as well. A new survey of emergency room physicians recently found the number one reason doctors order many tests is to protect themselves from lawsuits.