Feature

Figuring out league tables

Hospital league tables might be a good idea if the right information was being collected, says the Radical Statistics Health Group

In June 1994, the Department of Health (DoH) published league tables for English hospitals and ambulance services. The data in the tables were intended to tell the public about ‘the quality of service which you are entitled to expect from your NHS’.¹

The indicators used are the percentages of patients seen within 30 minutes of their appointment time or within five minutes of arriving in accident and emergency departments, the numbers of patients not admitted within a month of the second cancellation of their operation, the percentages of operations done as day cases, the percentages of people waiting more than three and 12 months for hospital admission and the times taken by ambulances to arrive. So they relate to how long people have to wait rather than to the quality or outcome of the care they are waiting for.

Since the league tables were published, waiting times for hospital admission have continued to be in the news. Data published in press releases and statistical bulletins have shown a continuing fall in the numbers of people recorded as waiting more than a year for hospital treatment.² In response to criticisms that waiting times for outpatient appointments were not included, the DoH has started to collect these data and the first provisional figures have been published.³

Other data have been less prominent, notably the numbers of people recorded as having ‘self-deferred’. These are people who are offered a date but are unable to attend. Their waiting times are then calculated from the most recent date offered irrespective of how long they had been waiting before the offer was made.¹ Their numbers have risen, as figure 1 shows.⁴ In the past, data were collected about the numbers of people who were removed from the list on the grounds that they no longer required treatment. This could arise if they had been treated elsewhere or had died. Their numbers rose from 90,550 in the six month period ending in September 1988 to 168,918 in the six month period ending in March 1991.⁴ It is likely that as hospitals came under increasing pressure to reduce the numbers of people stated to be waiting for long periods, they made more careful checks on the people on their lists. Now the numbers of people removed from waiting lists for reasons other than treatment are ‘not held centrally’ by the DoH,⁴ making it impossible to speculate about their importance.

Government ministers insist that it is only waiting times which matter and not the numbers of people on the lists. The concentration on times ignores variations in the severity of the conditions for which people are awaiting treatment, and in resultant disability. It may also be a response to the continuing rise in the numbers on the lists, shown in figure 2.

The issue of whether league tables should include hospital mortality rates has generated much media comment. In fact, these rates have been available for some years in the DoH’s collection of health service indicators, but have been rightly ignored since they are impossible to interpret.⁶ First, they do not take account of where people with terminal illnesses choose to spend their last days and second, they make no allowance for differences in the populations the hospitals serve.

Hospital mortality rates for Scotland were published in December 1994 as part of a series of clinical outcome indicators. Scotland has a much more fully developed statistical system than England and it was possible to adjust for some, though not all, of the relevant differences between hospitals. Further, it was emphasised that the data were not intended to be used as league tables.⁷

Of course, it is unlikely that there are no important differences between hospitals in the quality and outcomes of their care, but the crude indicators in the league tables are little help in assessing these. Better data collection systems are needed to generate more appropriate indicators which are sensitive to the quality and outcomes of care and adjust for differences in populations. More research is also needed on the effectiveness of care being offered.