HCUP's 2012 National Inpatient Sample (NIS) was redesigned to improve national estimates. The 2012 NIS will be released in June. A complete description of the redesign is in the Nationwide Sample Redesign Final Report.

The redesign has three main changes:

• Revisions to the sample design, which now creates a sample of discharge records from all HCUP-participating hospitals rather than all discharge records from a sample of hospitals
• Revisions to the definition of the discharge universe
• Revisions to enhance confidentiality by eliminating State identifiers and data elements that are not uniformly available across States

These changes result in reductions in sampling error, producing even better national estimates than the previous NIS.