Variability. Six states—California, Connecticut, Florida, Maryland, New York, and Ohio—and numerous insurers were included in this report. The percentage of overturned coverage denials spanned a range both among the states and the insurers.

Type. Just as the most common errors that taxpayers make in completing tax forms are forgetting to sign the return and transposing numbers, so too the most common errors in filing insurance claims involve missing, incomplete, or incorrectly entered information. Regarding eligibility, this may include failure to get preauthorization prior to providing a service (if this is required) or initiating service prior to the date that coverage was initiated or after coverage was terminated

Coverage. Insurers may deny coverage before or after the service has been provided. Claims denied as a result of judgments about the appropriateness of the service can be overturned with appropriate documentation. Appeals for claims can be reviewed internally by the insurer, but may also be requested and reviewed by an independent reviewer. Data from four of the six states showed that between 39% and 59% of internal appeals preserved the coverage denial. In the current study, between 23% and 54% of externally reviewed appeals were reversed or revised. The reversals occurred because either the consumer or the provider submitted additional information (e.g., medical records).