The launch of a consumer hospital guide ranking hospitals by death rates has sparked attacks on the quality of its data and the workload imposed on the NHS by private publishing company Dr Foster.

One HSJ source said those involved in collating data in his region felt that 'people in the NHS have been working our arses off to give this private outfit a fat profit'.

And a health commentator who turned down an invitation to join the project's ethics committee questioned the quality of the data gathered and suggested that members of the committee had given the project 'added kudos' without having 'much real input'.

An invitation sent to Roy Lilley last summer offered reassurances that 'membership of the committee is not an onerous task', with contact largely by e-mail to create 'as small a workload as possible for members'.

Mr Lilley also attacked the questionnaire sent out to trusts. And he questioned the validity of data which led the guide to draw a strong link between numbers of doctors and death rates.

'The doctor-bed ratio is nonsense: some hospitals provide a community service, so have more doctors and fewer beds, ' he added.

The two-part survey launched in last week's Sunday Times looked at death rates at 174 English acute trusts and other health indicators in hospitals throughout the UK and Ireland.

Despite insisting that 'this is not a league table', the company produced a top-20 and bottom-20 ranking of hospitals by death rate.

Healthcare information publisher Dr Foster claimed 'the Department of Health supports this project at ministerial level' and also said the DoH had told regional offices to advise trusts to take part in the survey. A spokesman for the DoH said he was not aware of such advice being given. He said: 'We absolutely support the principle of providing accessible, accurate information about the NHS, with the proviso that the word accurate is important. I understand a couple of trusts are concerned about whether their data is correct.'

John Appleby, director of the health systems programme at the King's Fund, said he had no qualms about ranking hospitals, but questioned whether the Dr Foster data was any more valuable than many of the other performance indicators.

'This is an indicator of what? It is an indicator of how many people died in hospital. Most people die in their own homes, so this covers a fairly small proportion.'

Mr Appleby said he would be 'perfectly happy to go to a hospital in Walsall' which came bottom of the table, and asked what the motivations of the company were in an exercise which 'adds another bit of pressure on the service'.

Dr Foster flagged up its ethics committee, which includes well respected names such as Professor Sir George Alberti, president of the Royal College of Physicians, Sir Donald Irvine, president of the General Medical Council, and Dr Michael Dixon, chair of the NHS Alliance.

Dr Dixon admitted the input of the committee 'was not great, but I do not think that was our role'. He described the findings as 'just a first stab' at producing data.

HSJ sources said research did not appear to have taken enough account of factors such as comorbidity and deprivation.

Dr Foster said the mortality index was based on research by Sir Brian Jarman, emeritus professor at Imperial College of Science and Technology and Medicine.

Sir Brian's son, Dr Julian Jarman, who is Dr Foster's medical editor, told HSJ that the data had examined factors such as comorbidity and deprivation once figures had been standardised by diagnosis, length of stay and type of admission. Analysis of these figures showed that comorbidity and deprivation 'were not powerful' factors, he added.

Tim Kelsey, managing director of Dr Foster, said the project was a great example of the private sector taking 'some of the strain off the NHS'.