Using official figures, it assesses how many deaths actually occurred at an acute trust compared with how many were predicted given the types of patients treated.
For the first time, it uses four different methods of calculating mortality rates including deaths after surgery and deaths among low-risk patients, in order to give as full as possible a picture of the care delivered at a hospital.
It also reveals the places where patients face worse care at weekends and overnight, often because fewer senior doctors are on duty, as our front-page story shows.
In addition, the report identifies hospitals where elderly patients have to wait too long for emergency hip operations, and looks at success rates for planned joint replacement surgery at private sector units as well as NHS ones.
Full details can be found at www.drfosterhealth.co.uk
Search the map using the first half of your post code (e.g. in bold, SW1W 0DT) or by searching your NHS trust's name.
1. Death rates means the hospital standardised mortality ratio (HSMR), a measure of deaths while in hospital care based on 56 conditions, representing 80 per cent of deaths. High ratios are bad (in general, more than 100) and can be used to identify underlying problems.
2. Weekend mortality means the death rate (see note 1) on the weekend. Nation wide, patients are 10 per cent more likely to die if they are admitted over the weekend.
3. Hip operations measures the percentage of patients requiring emergency hip fracture surgery operated on within two days. Waiting too long for surgery can increase the death rate (see note 1).
4. Low operation frequency refers to the number of abdominal aortic aneurysm surgeries carried out in the last year. If a hospital has carried out fewer than 35 such surgeries, the patient is at a higher risk of dying (up to 70 per cent in some cases).
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