At dawn on the 17th of November, Andrew Lansley and I appeared together on Radio 5 Live for the Government’s pre-announcement of its new waiting times target. It was a friendly affair rather than a duel, because the new target is very welcome and so we were in the happy position of agreeing with each other.

Why is it so welcome? If you’ve been following this blog for a while, you will know that I am a longstanding critic of the main existing target (that 90 per cent of admitted patients must have waited less than 18 weeks since referral). The reason, quite simply, is that if you have lots of long-waiters then the target restricts your ability to treat them.

The new target is much better because it stops the backlog of long-waiters from building up in the first place. The target, which is confirmed in the new Operating Framework (para. 2.31), is:

that 92 per cent of patients on an incomplete pathway should have been waiting no more than 18 weeks. The referral to treatment (RTT) operational standards should be achieved in each specialty by every organisation and this will be monitored monthly.

The NHS has never actually achieved this level of performance, although it did come very close last year, achieving 91.9 per cent of the waiting list within 18 weeks at the time of the General Election. How hard will it be to achieve?

The statement issued to the media by the Department of Health estimated that “In practice, the new standard will mean the NHS will have to trim about 50,000 from its waiting lists”. I couldn’t quite replicate this figure, but as we’ll see in a moment it is as good an estimate as any. At 2 per cent of the waiting list, or 4 per cent of monthly activity, it doesn’t sound too hard.

There are various ways of looking at the numbers. If we simply take the total size of the waiting list (2,586,583) and the current number waiting over 18 weeks (242,540), then to achieve the target by cutting the backlog we need to reduce the list size by 38,710 (bearing in mind that both the total list and the over-18-week waiters are being reduced at the same time).

That calculation assumes that we can net-off the under-achieving services against the over-achieving ones. In practice, though, the target must be met in every service. If we tackle the target by brute force by treating the backlog, without netting-off pressures between one service and another, we find that a heftier 90,000 extra activity would be needed to bring the existing backlogs down to target level. This still doesn’t look too bad, at only 0.6 per cent of annual (admitted and non-admitted) activity.

But, as usual with NHS pressures, the challenge is not spread evenly around the NHS. It is clustered. Taking all specialties together, here is a map showing the waiting time exceeded by the top 8% of patients on the list (all data is for September 2011 from DH):

We can get a better picture by going right down to specialty level; there are 1,330 services (by Trust, by specialty) that have more than 50 admissions per month. Some 61 per cent of them are already achieving the new target. We estimate that about 22 per cent more could achieve the target safely with good scheduling alone, without needed to reduce the size of the waiting list. That leaves just 17 per cent that would need to reduce the size of the waiting list (in addition to good scheduling).

(You might guess from those proportions that the England-wide target could be met with good scheduling alone, and you would be right. In fact, if every service implemented good scheduling then we estimate the target could be met nationally even if the English waiting list grew by 50,000.)

When analysing the pressures in each service, we really want to know how many working days it will take to clear the backlog. We want to draw attention to those services that have the biggest pressures. Ideally, we also want to know whether we can get part-way there by scheduling patients in a better order.

The next chart has a go at this. The size of each bubble shows the number of over-18-week waiters at each Trust (considering all specialties together, for now). Its position along the horizontal (x-) axis shows how many working days it would take to achieve the new target, if each Trust simply tackled its backlog starting with the longest-waiting patients (and did so at the rate the Trust currently treats both admitted and non-admitted patients). For comparison, the bubble’s position up the vertical (y-) axis shows how many working days it would take to achieve the target, if good scheduling were also put in place (and, because the necessary details are not published for each Trust, we have had to make a few assumptions about what good scheduling might look like).

Most of the Trusts are piled in a heap around where the axes cross; they don’t need to do much, if anything, to achieve the new target. Then we have a few going out along the horizontal axis, who could achieve the target just by scheduling their patients in a better order; no extra activity is required. Then, rising up the chart, come the big blobs with the biggest problems; these are Trusts where good scheduling isn’t going to save them; somehow they need to cut their waiting lists in a fairly serious way. The four biggest ones from the top right are: Kingston, Taunton, Wirral, and St George’s; all currently have 8 per cent of their waiting list over 26 weeks, and will face a challenge to get that down to 18 weeks.

An all-specialties view is all very interesting, but in practice a gynaecologist isn’t going to be much help with the gastro backlog. So here is the same style of chart for each specialty; one blob per Trust, with the specialty name shown in the bottom right corner of each chart:

As we found previously with one-year-waiters, some of the biggest pressures are found in gastroenterology and “other specialties”. Neurosurgery is also an area for concern, because there are large pressures and because not many Trusts provide this highly-specialised service. You may be wondering if your Trust is one of the pressured ones, so the highest clearance times in the charts above (according to backlog clearance time alone) are:

In conclusion, the new target is within reach for the NHS as a whole. Things may slip over the winter but, come the spring, the target should be achievable nationally as Trusts improve their waiting management and recover the winter backlog.

Looking in greater detail, there are many Trusts and specialties (we estimate around 17 per cent) where some backlog clearance will be required. Within that, some have very challenging positions and may need help from their neighbours with their backlog clearance. In all cases good planning, using an advanced planning tool that models waiting time dynamics, will help Trusts and Commissioners to ensure that recurring and non-recurring resources are deployed to achieve the new target sustainably.

This post first appeared at HSJ blogs