The NHS has been ranked 18th in a revised league table of global healthcare systems.
The researchers say these new rankings are more accurate
Three years ago, the World Health Organization (WHO) ranked the UK 10th. However, experts criticised the scoring saying it gave a misleading picture.
British researchers have now re-scored the countries.
By their calculations, Sweden, ranked 4th in the WHO table, now has the best health system, while Japan drops from 1st to 13th.
The WHO rankings were based on an analysis of health outcomes, responsiveness and
It was criticised for looking at deaths from all causes, no matter what the causes were.
Many experts suggested a table looking only at those deaths that could be avoided through timely and effective health care, such as cancers and diabetes, would be better.
This would mean that the performance of the health systems would be separated
out from other factors such as diet and smoking rates, accidents and suicides.
That is what researchers from the London School of Hygiene and Tropical Medicine have now done.
They restricted their analysis to healthcare systems in 19 industrialised countries.
Countries like Japan, Italy and Greece which did well in the WHO rankings have done less well this time around.
Countries like Canada, Finland and Sweden which did not fare particularly well three years ago have done much better.
The UK's fall of eight places leaves it just one place off the bottom. Only Portugal's healthcare system was ranked worse.
"We have looked at how the WHO's rankings of health system performance would change if only those causes amenable to health care were included," said Dr Ellen Nolte, one of the report's authors.
"They show that, for some countries, the differences would be very substantial."
She suggested WHO should use their methodology when it next publishes its league table of global healthcare systems.