NEW Welsh hospital death rates have been published, as debate continues about how meaningful they are in measuring quality of care.
And the latest figures, four sets with three different criteria, are unlikely to ease confusion about their ultimate worth.
Two sets of figures for Welsh hospitals, for 2012 and 2013, show rates according to a UK-wide measure, the Risk Adjusted Mortality Index (RAMI).
Another set, the Welsh RAMI, is adjusted to take into account Welsh population trends.
A fourth, the Summary Hospital-level Mortality Indicator, is based on deaths in hospitals.
In each set, outcomes for 18 featured Welsh hospitals are often significantly different.
The view is muddied further because 2013 UK RAMI figures include palliative care patients, unlike those for 2012.
The issue has been in the headlines since it was revealed last month that NHS England medical director Sir Bruce Keogh raised his concerns about perceived high rates in some Welsh health boards after he was passed figures by Cynon Valley MP Ann Clwyd.
She has since continued to call for an investigation into this and other issues in the NHS in Wales, invoking the wrath this week of First Minister Carwyn Jones, who said she was "denigrating" the service.
Wales' Deputy Chief Medical Officer Dr Chris Jones - with whom Sir Bruce Keogh has raised the issue of death rates - said such rates alone cannot be relied on to assess individual hospitals' performance, and figures show that depending on the system used, these rates can vary considerably, "highlighting the difficulty in using it to judge the quality of care provided."
A new system will be developed based on a range of measures, and there will also be a review of how the NHS collects and uses data to measure Welsh hospitals' death rates. This will include a focus on figures from six hospitals where the Welsh RAMI score for 2013 was above the benchmark 100.
Dr Jones said the Welsh RAMI is "potentially the most meaningful" of the figures, as it represents an attempt to take into account issues relating to Wales, such as socio-economic factors and lifestyle issues such as smoking. Also, more people in Wales go into hospital when they are terminally ill.
The 2013 Welsh RAMI score for the Royal Gwent is 96, for Nevill Hall 88, and for Ysbyty Ystrad Fawr 86. But all three had 2013 UK-wide RAMI scores above 100.
Overall, six hospitals had Welsh RAMI scores above 100, but 15 topped 100 based on the UK RAMI measure.