Michael McWilliams, an assistant professor of health care policy and of medicine at Harvard Medical School, counters Megan:

From the sizable observational literature, McArdle selects just one negative study to suggest insurance coverage may not affect mortality (Kronick 2009).  Yet several other observational studies that controlled for an equally robust set of characteristics have consistently demonstrated a 35-43% greater risk of death within 8-10 years for adults who were uninsured at baseline and even higher relative risks for older uninsured adults with treatable chronic conditions such as diabetes and hypertension (Baker et al. 2006; McWilliams et al. 2004; Wilper et al. 2009).

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