The NHS may have to prioritise the less sick to recover elective performance

In any system that involves queuing – whether at the supermarket checkout or for surgery – how long you wait is determined by three factors. It matters how long the queue is when you join it, how fast the queue is moving, and how waiters are chosen to be seen next: “first come first served”, or some other method. For elective activity in the NHS, this means that there are three determinants of waiting times: the number of people being referred to join the waiting list, the capacity of the NHS to treat people, and the ways that different groups of waiters are prioritised.

NHS England’s recent elective reform plan aims to make changes to these factors to improve performance against the headline 18-week target. The rapid expansion of Advice and Guidance services aims to reduce the number referred to the list, for example, while the plans to raise productivity aim to increase the number of patients that can be treated.

Reducing demand and increasing treatment volumes can be expected to shrink the size of the overall list, but there is no simple read-across to waiting times – and it is waiting times that the government has chosen to focus on. Eighteen-week performance was 59 per cent in September 2007, 71 per cent in April 2020 and 90 per cent in July 2017. But in these months, the total size of the list was almost identical at 4 million. As Rob Findlay has often argued in HSJ, to understand waiting times, we need to look at the shape, as well as the size, of the waiting list. This depends a great deal on who is treated and in what order.

This week we have published new simulation modelling of the elective waiting list. Our model takes into account these complex waiting time dynamics, including the factors that determine the shape of the waiting list. This allows us to explicitly quantify what would have to happen for the 18-week target to be met.

The first way to improve waiting times is to treat more patients. But this alone is unlikely to be enough. Our modelling suggests that 4.9 per cent annual activity growth would be needed if all other factors (discussed below) remain at current levels. For comparison, activity grew by 3.8 per cent in 2024 and by an average of 2.4 per cent each year from 2016 to 2019. Although not impossible, we judge this level of sustained treatment growth to be highly unlikely. Under a more plausible (but still ambitious) 3.5 per cent annual activity growth rate, we estimate that 18-week performance will hit 74 per cent by mid-2029. That’s an improvement relative to the 59 per cent who are waiting fewer than 18 weeks now, but far from the 92 per cent target.

The second way to improve waiting times is to reduce the number of referrals. We estimate that a plausible reduction in demand – combined with 3.5 per cent annual growth in activity – could get 18-week performance to 82 per cent by mid-2029. Reducing demand can therefore take the NHS closer than if it relies on increasing activity alone, but likely not, in our judgement, all of the way there.

The final way to improve waiting times is to change which patients hospitals treat first from the waiting list. The choice of which patients to prioritise is mainly a clinical decision. But if meeting the 18-week target is the main objective, then prioritising those who have been waiting longer than 18 weeks (ahead of those who haven’t been waiting so long) would help to meet it. There’s precedent for this: the previous government shifted more activity towards those who had been waiting the longest. We estimate that this one plausible scenario for reprioritisation, in line with changes we see from how hospitals responded to previous targets, combined with the 3.5 per cent annual growth in activity and demand reductions discussed above, could get 18-week performance to 86 per cent by mid-2029: a major improvement, but still shy of the magic 92 per cent.

None of these policies come without other costs. Aiming to reduce the number of referrals risks some patients not receiving the elective care they genuinely need. Prioritising one group of patients (those who have waited longer than 18 weeks) means deprioritising others (those who have more recently joined the list – many of whom may have the most severe medical needs).

Yet these may be trade-offs that NHS leaders are willing to – or have to – make. Aiming to get to 92 per cent by mid-2029 is, given the starting point, genuinely ambitious. Our modelling suggests that getting there will require ambitious steps to be taken on activity growth, demand reduction and reprioritisation all at once. Increasing treatment volumes alone will likely not suffice – the other levers will need to be pulled simultaneously, and hard. Otherwise, come the end of the Parliament, we might still be waiting for the 18-week target to be met. 

This article was first published in Health Service Journal and is reproduced here with kind permission.