In the article “A Longitudinal Examination of Hospital Registered Nurse Staffing and Quality of Care” (Marks, Harless, McCue, Xu, Health Services Research 39 (2):279–300), an error was made in the listing of states participating in the sample (281). The authors inadvertently included Oregon and omitted California. The sentence should read as follows:

These 422 hospitals, 49 percent of the HCUP base year sample, are located in 11 states (Arizona, California, Florida, Illinois, Iowa, Massachusetts, New Jersey, Oregon, Pennsylvania, Washington and Wisconsin).

The authors apologize for any confusion.