Researchers say that more study is needed to draw conclusions about the effects of recent reforms on hospital quality.
Professor Gwyn Bevan and Matthew Skellern at the London School of Economics and Political Science argue that the jury is still out on the effects of hospital competition on quality of care within the English NHS.
Their views come as the Health and Social Care Bill has its second reading in the House of Lords on Tuesday 11 October.
The health secretary, Andrew Lansley, has proposed changes to the English NHS that will extend the hospital market introduced by "New Labour" in the 2000s. This was the second era of hospital competition within the NHS; the first, the "internal market," applied throughout the UK from 1991 to 1997.
Bevan and Skellern review evidence from three recent econometric studies of the New Labour market, which all show a seemingly causal relation between greater competition and lower hospital mortality. These studies have proved highly controversial because they contradict previous findings that competition in the NHS was largely ineffective, or even had negative consequences.
The authors argue that the three recent econometric studies are "serious and rigorous responses to the challenge of estimating the effects of competition on hospital outcomes." However, they question their use of hospital mortality rates (HMRs) to judge the impact of competition on the quality of elective surgery because deaths following elective surgery are so rare that another measure is needed to assess its quality.
Two econometric studies examining the effects of introducing patient choice in elective surgery assume that this competition will improve elective surgery, which will require improving hospital management in ways that lead to across the board improvements in hospital quality. The authors argue that: "It is equally plausible, however, that such competition for elective surgery might, through diversion of management effort, negatively affect the quality of other hospital services." Hence the authors believe that "a key finding of these two studies is that introducing patient choice for elective surgery in the New Labour market did not reduce quality elsewhere in hospitals."
"We believe there are strong grounds for introducing patient choice into the NHS as an end in itself, given its potential to empower patients and give them greater control over the conditions of their care," say the authors. Nevertheless, they add, how patient choice has affected outcomes in elective surgery "remains an open question."
They conclude: "More research is required before conclusions can be drawn about the effect of recent reforms on hospital quality, let alone about the merits of the Mr Lansley's proposals further to extend competition."