So here’s the situation. Your clinics are completely booked up with routine referrals for the next six weeks. But now an urgent referral comes in; the patient has something potentially nasty and you need to see them within two or three weeks. How do you squeeze them in?

If urgent referrals are very rare events, then you might force this patient onto a clinic by over-running the session, or cancelling another patient to make space. But let’s say urgent referrals are a normal part of your practice – what then?

One way or another, you need to make some allowance for them; the question is how. When a clinic is “completely booked for the next six weeks”, does that really mean that every minute for every doctor in every session is booked? Or do you only book 3 hours of each session, in the knowledge that a bit of time will probably be needed to squeeze in an urgent referral or two? Or do you regard follow-up patients as cancellation-fodder whenever extra time is needed? Or do you book the clinic not the doctors, so that each doctor is under-utilised?

None of these options looks very palatable in cold print. Wasting doctor time is the worst of all sins, because it inevitably means less-productive consultants, less-experienced juniors, longer waiting lists, and longer waiting times. Regularly cancelling follow-ups is either clinically risky for the cancelled patients (if the follow-ups are necessary) or a sign that too many patients are being followed-up (if they aren’t); in any case those follow-ups will only need to be rebooked later on, so the problem is deferred not solved.

The best approach is surely to plan for all doctor time to be fully utilised, and then carve out enough time for follow-ups (who are often entirely predictable well into the future: “come back in six months” means the need for that follow-up slot is known six months in advance). The remaining capacity is then available for new patients; some should be booked up with routine referrals, but some should be reserved for urgent referrals. So the question is: how much?

It turns out that the worst number of urgent slots is somewhat too many. On the assumption that patients are being booked using the best booking rules (you can learn all about those using our patient booking simulator), the following chart shows how performance varies with the number of urgent slots. In this chart, demerit points are awarded for different kinds of undesirable event: delayed urgent patients, delayed routine patients, rebooking patients, and booking patients at very short notice.

A lower demerit score means a better performance, so in this example (where 40% of referrals are urgent), the best performance comes from having 43% of slots reserved for urgent referrals.

You can use the booking rules calculator in our simulator to work out the right number of urgent slots for your clinic. You’ll see that it depends on more than the number of urgent patients: the amount of other disruption such as cancellations matters too, as does the choice of a fully-booked or partially-booked clinic.

Happily, other factors such as the number of patients waiting, how quickly urgent patients need to be seen, whether waiting lists are pooled between consultants or not, and the amount of random variation in the referrals rate, turn out to make no significant difference to the number of urgent slots required. Some of these do affect overall performance though, but we will have to leave that to a further post.

For full details of our research into reserving urgent slots, ask for our Gooroo Waiting Times Research White Paper 2.