A clued-up 18-weeks manager put me on the spot recently. We manage patient bookings according to their position on the whole 18 week pathway, she said. How do you model that?

My first answer was the usual one: it’s best to model each stage of the pathway separately. That way you get systematic management and planning at each step, and the outpatient booking department isn’t tempted to pass on its waiting time problems for the inpatient department to solve later.

Ah, she said, but we’re a small Trust, and we just have one booking office for all stages of the pathway. What you say is fair enough if all patients follow the same pathway; but what if some have a diagnostic stage and some don’t? Then modelling each stage separately won’t work because, at the inpatient stage, the post-diagnostic patients are much closer to 18 weeks than the others.

Well, that was a tougher question, and I didn’t have an answer to hand. Multi-stage, multi-strand pathways would be tough to model properly (taking into account clinical priorities, cancellations, booking rules, etc) and I’m not aware of anyone having done it. But it’s a good question and it deserves an answer, and after thinking about it I think the answer is this.

Booking

The scenario we are talking about is:

Let’s start with the practicalities of managing patient bookings on this pathway. The outpatient stage is a genuine single-stage booking process, and is directly suitable for good booking techniques that achieve 100 per cent slot utilisation, shorter waits, protected clinical priorities, and minimised disruption.

Then at the diagnostic stage, patients can be added to the waiting list with their original referral date, and flagged if they suffered cancellation in outpatients. This ensures that those who have already waited longest are booked first, and that previously-cancelled patients receive preferential treatment (and have capacity set aside for them). Apart from that, the diagnostic stage can also be managed as a straightforward single-stage booking process.

The inpatient stage is more complex, because the major pathway split at the diagnostic stage means there are two quite distinct classes of routine patient, with quite different waiting time histories. Nevertheless, if the inpatient stage is managed using a partial booking system and patients are added to the waiting list with their original referral dates, then I think it can also be managed as a straightforward single-stage process.

Under a partial booking system, appointments are only issued a certain number of weeks ahead, so those patients who bypassed the diagnostic stage will wait a few weeks before being given their appointments, whereas patients who had a diagnostic will be given appointments soon after being added to the inpatient list. This restores evenness to the two halves of the pathway, and allows the 18 week target to be achieved across both parts of the pathway, with the largest possible total waiting list.

Planning

What about planning? When it comes to planning future activity to achieve the 18 week operating standard, the outpatient stage can be modelled as a single stage, as above. After that point, if you do want to model the split pathway, I think it makes sense to split it (for planning purposes only) all the way to the end, so that it looks like this:

So, for example, your planning might involve working out the activity, capacity and cost required to achieve 90 per cent treated within:

• 6 weeks, for outpatients
• 6 weeks, for diagnostics
• 6 weeks, for post-diagnostic inpatients
• 12 weeks, for non-diagnostic inpatients

That way, you are planning to achieve the overall 18-week target, but still taking advantage of the longer waits available on the non-diagnostic inpatient path.

Incidentally, whilst it is fine to split the pathway like this for planning purposes, it is usually better to avoid splitting an operational booking system. The differences in waiting times between one consultant and another are bad enough, without adding any further splits.