To achieve a total process time of 18 weeks from GP referral to first treatment, there must be no waiting list delaying any of the hundreds of administrative and clinical tasks required to get a patient safely through the system. So what is the process?

To achieve a total process time of 18 weeks from GP referral to first treatment, there must be no waiting list delaying any of the hundreds of administrative and clinical tasks required to get a patient safely through the system. So what is the process?

1. Commissioners and specialty managers need a high-level process map of the six to eight key steps involved in getting patients with the most common clinical conditions through the system.

These steps might be as follows: making the first appointment; conducting the first clinic appointment; carrying out tests; conducting the second appointment and making a decision on treatment; adding the patient to the waiting list; conducting pre-operation assessments; admitting and treating the patient; conducting a post-procedure follow-up and conducting a six-week follow-up.

The same process map will not apply to all conditions, as the time taken for patients at each step in the process will vary. However, certain clinical conditions may share a process map.

2. Systems need to be set up to measure improvement. We need a run chart to show the time taken (in days) from referral to first treatment (y-axis) for sequential patients (x-axis) and the variation. What is the time currently taken for 99.9 per cent of patients (the upper process limit)? Mark in the target for March and December 2008. The aim is to bring the upper process limit down to meet the target.

Before we consider how to eliminate the backlog, we must ensure that the variation mismatches between the demand and the capacity at each step do not continue to form waiting lists.

3. Run charts with at least 20 weeks' worth of data are required to show the variation in demand at each step: the number of GP referrals, the number of patients being referred for each test type, requests for follow-ups, additions to the waiting list, requests for post-treatment reviews and so on.

4. To keep the waiting lists from building up, the average weekly capacity at each step must be no less than 80 per cent of the peaks in 'normal' variation in demand. The demand run charts will give the number of slots required to keep waiting lists from forming at each step. Now we need to know the time taken to process 80 per cent of patients at each step to convert the demand into time.

5. The current capacity is the time allocated for each step in the pathway according to the timetables and work plans. Have we got the average capacity required to deal with the variations in demand at each step?

6. We then need to calculate the additional capacity needed to process the backlog. If we know the total backlog at each step, we can calculate the number of slots required in the short term to drain out the backlog at each stage. Remember, as the backlog is reduced, additional short-term capacity will be required at subsequent steps.

Making the system affordable will require imaginative ways to increase effective capacity by reducing the steps and variation in the process, for example by pooling referrals and reducing current carve-outs.

Dr Kate Silvester is national coach for the Osprey programme, which gives clinicians a chance to learn and apply manufacturing and engineering techniques to improve timeliness, cost, efficiency and quality.