What are the limitations of the data?
Apart from occasional inaccuracies in the data, there are other limits to what the data can tell us about surgery outcomes. There are factors that affect a child’s chances of survival that are not routinely collected for by national bodies and so cannot be captured by a formula that was developed using national data. These data are also snapshots in time of what happened at each hospital. A run of unforeseeable factors could cause a very good hospital to have worse outcomes than predicted, so we need to be careful about reading too much into results from any single time period.
The data also can’t tell us about how or why a hospital achieved the recorded results, so it cannot, by itself, tell us whether one hospital offers better or worse quality care than any other. These data cannot tell you what the results are likely to be next year. It also cannot tell us anything about what happens to children who never get operated on for whatever reason, since data on these children is not currently submitted to national audit.
- Unforeseeable factors
It is impossible to predict precisely what is going to happen in an individual operation. This is partly due to the inevitable inability to predict the future with certainty – all people are physically unique and will react slightly differently to medicines, anaesthetic, surgery and no heart problem is exactly the same as another.
There are also factors that we suspect may influence the outcome but cannot be included in the statistical formula because no routine audit data on them is collected, for instance the size of a hole in the heart.
Together, we call these all “unforeseeable factors”.
