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Stockport PCT – Understanding Demand/Capacity and Waiting Times

A model of the contracted flow of activity in the Orthopaedic Assessment Service to determine if all patients could be seen within a 4 week period.


Stockport PCT experienced a rise in GP Referral to Secondary Care from April 2008 which coincided with the introduced of Free Choice in the Choose and Book system. Previously, if a G.P. made a referral to Trauma and Orthopaedics, General Surgery, Dermatology, Urology or Gynecology the Choose & Book system would direct the referral to the local Tier 2 service. In April 2008,’Free choice’ was introduced, which removed this facility and referrals to Tier 2 services fell.  In the first 6 months of 2008/2009 Tier 2 accounted for just 23% of total referrals, compared with 33% for the same period the previous year.

The PCT wanted to understand the effect of a change in demand on waiting times. The initial analysis centered on the Orthopaedic Assessment Service (OAS). Using Scenario Generator, the PCT modelled the contracted flow of activity to determine if it was feasible for all patients to be seen within a 4 weeks period.


The PCT built a pathway to simulate contracted levels of activity at each stage of the patient journey, assuming waiting times of:

The pathway is outlined below:


The results showed that, at the contracted levels of demand and capacity, 97% of patients could be seen within 28 days and 100% of patients could be seen within 37 days.


Simulation and modelling provided the PCT with a means of understanding the flow of patients from referral through to discharge, and the expected time taken during the process. From this position they expect to go on to examine the impact on waiting times if there is further demand on services, if the service is redesigned, or if there are changes to the capacity available in the system. A similar system can also be used to examine other pathways.

“This has helped us to understand current demand and flow, and will enable us to have a more meaningful dialogue with our providers about future contracting arrangements” –  Lisa Maginnis, Analyst, Stockport PCT

Tips for Other Users

“Always start with a simple question first, it will help you define the problem better and focus on the right details to help you get an answer”

Further Information

More information about Scenario Generator can be found at:


Stockport PCT


Simul8 and NHS Institute

Contact Person

Claire Cordeaux

Contact Email

claire.c [at]


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