Has open data led to better heart surgery survival rates?

"For example, five years ago, it was made far easier for the public to access, understand and use data on survival rates following heart surgery. And guess what happened? Those survival rates rose dramatically." David Cameron, Daily Telegraph, 6 July 2011

With the ongoing phone hacking scandal dominating the media agenda, the issue of data security is perhaps more sensitive than usual.

Readers of the Telegraph this morning might therefore have been surprised that the Prime Minister chose this moment to extol the Government's progress on its open data initiative.

Key to David Cameron's argument was the idea that better access to official information drives improvements in public service delivery. To illustrate the point, Mr Cameron gave the example of heart surgery survival rates, which he claimed "rose dramatically" after data was made public half a decade ago.

But is this link between open data and clinical outcomes as strong as this might suggest?

Analysis

After the Freedom of Information (FoI) Act came into force in England and Wales at the beginning of 2005, the Guardian newspaper submitted FoI requests to obtain mortality data for individual heart surgeons, which was published in April of that year.

Using this information, the Healthcare Commission (now the Care Quality Commission) and the Society for Cardiothoracic Surgery (SCTS) produced a web-based portal through which the public could access the results.

Updated results are still published by the Care Quality Commission, and using the time-series data we can see that heart surgery survival rates have indeed improved since the data was first unearthed by the Guardian in 2005.

However while this trend might, as the Royal College of Surgeons argues, suggest that "full audit has not resulted in risk-averse behaviour," it is less clear that it is the publication of this data itself that is "driving up performance."

As the SCTS's latest audit of the data — the Sixth National Adult Cardiac Surgical Database Report — suggests, earlier records of heart surgery survival rates have shown that the trend had been improving long before the release of data in 2005.

SCTS has been collecting mortality data on a voluntary basis from hospitals since 1977, and since 2001 some of this data has been publicly available. As the graphs below demonstrate, the improving trend in survival rates seems to be little affected by data publication.

  (Graph two shows data for years 1977-2000)   Conclusion   Of course the Prime Minister doesn't explicitly claim a causal link between data availability and improving heart surgery survival rates, and he is correct in identifying a rise over the past five years.   However in an article about the role open data has in "driving up" public sector performance, that inference is difficult to avoid. While the Royal College of Surgeons (among others) has defended the publication of mortality information by noting that fears about adverse clinical outcomes appeared to have been ungrounded, it is difficult to draw a direct link with any certainty between publication and improved results.   This is because a there is a long-established trend in risingsurvival rates dating back to when data was first collected in 1977, and SCTS — which compiles the data — has identified better clinical practices, such as the increased success of arterial grafts, as the primary driver.