Black patients and white patients are to a large extent treated by different physicians. The physicians treating black patients may be less well trained clinically and may have less access to important clinical resources than physicians treating white patients. Further research should be conducted to address the extent to which these differences may be responsible for disparities in health care.

Daily use of electronic cigarettes for at least 1 month is strongly associated with quitting smoking at follow-up. Further investigation of the underlying reasons for intensive versus intermittent use will help shed light on the mechanisms underlying the associations between e-cigarette use, motivation to quit, and smoking cessation.

Two of the five CAHPS 2.0 reporting composites have high internal consistency and plan-level reliability. The other three summary measures were reliable at the plan level and approach acceptable levels of internal consistency. Some of the items that form the CAHPS 2.0 adult core survey, such as the measure of waiting times in the doctor's office, could be improved. The five-dimension model of consumer assessments best fits the data among the privately insured; therefore, consumer reports using CAHPS surveys should provide feedback using five composites.

Delivery of routine preventive services is suboptimal for Medicare beneficiaries. However, patients treated within particular practice settings and by particular subgroups of physicians are at particular risk of low-quality care. Profiling these practices may help develop tailored interventions that can be directed to sites where the opportunities for quality improvement are greatest.

Lack of health insurance was the single most important factor in white-Hispanic differences for all three measures and for two of the white-African American differences. Income differences were the second most important factor, with one exception. Community characteristics generally were much less important, with one exception. The positive effects of insurance coverage in reducing disparities outweigh benefits of increasing physician charity care or access to emergency rooms.