If your waiting lists are growing, and you’re struggling to achieve your waiting time targets, then you try as hard as you can to get patients treated before they breach 18 weeks. As time goes by, more and more of your capacity is taken up by patients waiting 16 or 17 weeks, leaving less and less capacity for patients who haven’t waited so long.

Eventually you reach a point where nearly all your capacity is devoted either to patients nearing 18 weeks, or to patients who are clinically urgent. Then your waiting list grows a little bit more. Now what? Do you breach the target? Or do you squeeze a little harder, even if that means making urgent patients wait longer than they should?

If this was happening at my local hospital, then I know for certain what I’d want them to do: breach the target. Of course I’d rather their routine waits were short. But more important is the confidence that I’ll be treated quickly if there’s something seriously wrong with me.

Which option do NHS hospitals take in real life? To find out, here are the latest (Sept 2010) figures for General Surgery, presented in a new chart style that I’ll explain below:

In this chart, each bubble is an NHS Trust. The size of the bubble shows how many patients were treated during the month, and the centre of the bubble shows its position on the chart.

Over on the extreme left of the chart are Trusts with no 18 week problems at all. Some of them (the ones at the top left) have such small waiting lists that the majority of their patients are being treated within 4 weeks of referral.

Moving towards the right a bit, we come to a big cluster of Trusts all piled on top of each other. This is the middle of the pack: Trusts that have to make an effort to achieve the target (i.e. that fewer than 10% of patients should exceed an 18 week wait from referral to treatment (RTT); indicated by the vertical line). These Trusts still have significant waiting lists, and are mostly treating 20-30% of patients within 4 weeks, which we will take to be a reasonable indication of the underlying rate of clinical urgency in this specialty at a typical Trust. The range of urgency seen is illustrated by the horizontal lines, which show the 10th, 25th, 50th, 75th and 90th centiles for the percentage treated within 4 weeks RTT (weighted for activity).

Looking to the right of the vertical line, we come to those trusts that are breaching the 18 week target. The first few are at similar heights to the main cluster, showing that a similar proportion of patients is being treated urgently within 4 weeks. But as we move further and further to the right, to Trusts that are further and further from achieving the target, something interesting starts to happen. The bubbles get lower. Fewer patients are being admitted urgently.

Is this evidence of Trusts trying too hard to meet the 18 week target, and compromising clinical priorities in the process? Or is there an alternative explanation? For instance, these hospitals might have a cancer centre just down the road, but do no cancer surgery themselves, which would be a perfectly reasonable justification for the lower urgency rate.

The right-most bubble is in fact Norfolk and Norwich University Hospitals NHS Foundation Trust, and their complete RTT spectrum looks like this:

A lot of patients are being admitted from the middle (between 4 and 15 weeks), which suggests there may be scope to admit fewer patients from the middle of the list and devote more resources to patients approaching the 18 week target. However this is a big department with some 19 consultants and lots of subspecialisation, so it may be difficult to flex workloads between consultants to even out waiting time pressures.

What about the urgency rate? It’s a big hospital so we wouldn’t expect a low underlying urgency rate, but do we have numbers on this?The most recent figures I have for casemix are a few years old now and omit outpatients, but the most comparable figures I have is this: in 2006-07 the Trust was admitting 11% of General Surgery inpatients and daycases within 2 weeks, when you would expect them to admit 20% within 2 weeks (based on taking the national average 2-week admission rate at HRG level, and weighting it according to the local HRG mix.)

So on the face of it, albeit with lots of caveats, there does appear to be cause for concern. This specialty is having great difficulty with the 18 week target, and is (or at least was) admitting relatively few patients urgently, and yet a lot of capacity is being devoted to patients with intermediate waiting times. This suggests there is room to increase the rate of urgent treatment and improve 18-week performance, even if the size of the waiting list is not reduced, if (and it’s a sizeable if) it is possible to even out the waiting time pressures between different consultants.

So that was the national picture (with a local drill-down) for General Surgery. And here are three other specialties: orthopaedics, urology and ENT. Without giving a detailed commentary on each of them, I think there are useful questions that could be asked about some of the Trusts on each chart.