| Relationship with safety culture data | Proportion of staff at each hospital giving positive responses to the 2004 and 2005 NHS Staff Survey questions on safety culture and incident reporting, obtained from the Healthcare Commission website18 |
| Risk-management ratings per hospital awarded by the NHS Litigation Authority, ranging from 0 (lowest standard) to 3 (highest standard); data for December 2005 were obtained from the NHS Litigation Authority website19 |
| Relationship with reporting rates to other systems | No of reports of methicillin-resistant Staphylococcus aureus bacteraemias during 2004–2005, obtained from the Department of Health website16 |
| No of reports about medical devices to the Medicines and Healthcare Products Regulatory Agency (MHRA)17 during 2005, obtained from the MHRA via the NPSA |
| Relationship with outcome data | Hospital Standardised Mortality Ratios for each hospital for 2004–2005, obtained from the Dr Foster website22 |
| Hospital-level data on Patient Safety Indicators, measures of safety and quality which can be calculated using HES data. These indicators were adapted by the Healthcare Commission and the National Patient Safety Agency (NPSA) from those developed by the Agency for Healthcare Research and Quality in the US;23 data were provided by the NPSA |