NICE launched eighteen pathways yesterday, covering everything from neonatal jaundice to dementia. If it’s your job to plan NHS capacity into the future, how should you respond when pathway changes are on their way?

The point of planning is to prepare for the future. You can’t predict everything that is going to happen, but you do your best, accounting for foreseeable changes like trend demand growth, efforts to cut waiting list backlogs, demographic drift, and foreseeable pathway changes. This is why your plans are better than assuming the status quo.

Pathway changes are often the most complicated, because they are usually not representative of the specialty and so all the performance averages (such as lengths of stay) have to be changed too. So you can’t simply deduct a quantum of demand and leave everything else the same; you need to do something a bit cleverer.

Don’t change the future – rewrite the past

The best way to model upcoming pathway changes is to rewrite the past, as if the new pathway had always been in effect. So if a particular HRG is going to be managed out-of-hospital in future, then you need to filter that HRG out of your past activity data before passing it to a query (or to Gooroo Planner) to extract the information you need about activity, length of stay, clinical urgency rates, seasonal demand profiles, and so on.

If your pathway change has more complex effects then you may not be able to capture them with simple database queries that filter patients in or out based on things like age, postcode or HRG. If this complexity is significant and needs to be modelled explicitly, then a more specialist simulation model such as Scenario Generator can be used to model the pathway flows, get an indication of the effect on waiting times, and work out the implications for capacity.

If you need to look at waiting times more thoroughly, then Scenario Generator can be used to generate the rewritten past data that you need, on the new pathway basis, before passing it to Gooroo Planner for the detailed waiting time, capacity and financial calculations.

be specific about how care will change

So when you’ve been slaving away at next year’s plans, and somebody pops up with a challenge about a pathway change, don’t mutter something about estimating the effect on demand trends. Instead, you can ask them to be specific about the characteristics of the patients affected and how their care will change. If they deliver the goods, you’ll know what to do: rewrite history, and then use that as the basis for your new plan.