How can I use the data?

Facts about individual patients are highly confidential, and cannot be released to enquirers. However, it is normally acceptable to produce summary reports based on the contents of the records. For example, the total number of hip replacements can be found by searching the database for records that contain the appropriate procedure or intervention codes. In this case the resulting figure (many thousands per year) reveals nothing about the individuals concerned, and may be freely publicised.

The use of a data warehouse in this way provides a high degree of flexibility. Complex questions can be answered by identifying records that satisfy specific criteria. For example, how many women aged between 66 and 74 who were living in Manchester underwent complex heart surgery at a London hospital during the period April to September 2004? Because the records contain numerous dates, it is also possible to provide, for example, average lengths of stay in hospital and the time patients' spent on waiting lists before being admitted.

You could use HES data to answer a range of questions on:

• Diagnoses
• Procedures and interventions
• Healthcare resource groups
• NHS trusts
• Health authority areas
• Length of stay
• Waiting times
• Admission methods
• Age of patients
• Sex of patients
• Ethnic group of patients
• Maternity care
• Psychiatric care