Why is DGHPSim needed?

The DGHPSim suite is a set of stochastic simulation models that can be configured to fit the main features of any general hospital. The models simulate the working of an acute hospital in enough detail to investigate options for improved performance.

In England, NHS Trust performance is assessed by the Healthcare Commission in its annual health check that, amongst other things, stresses the importance of waiting lists and waiting times. The annual health check replaced star ratings, which seem to have been effective in reducing waiting lists and waiting times.

Waiting time targets that must be achieved by the end of 2008 include:

• A four hour maximum wait in A&E from arrival to admission, transfer or discharge.
• A two-week maximum wait from urgent GP referral to first outpatient appointment for all urgent suspected cancer referrals.
• A maximum two-week wait for rapid access chest pain clinics.
• A maximum of 18 weeks from GP referral to hospital treatment.

However, there is continuing concern that too much focus on one measure of waiting could have effects on other aspects of hospital performance. It has been known for many years that badly designed performance regimes lead to game playing by those whose performance is being measured. That is, targets may affect behaviour in ways other than those intended.

No one knows if it is possible for all hospitals to achieve these targets, since none has unlimited resources and must trade off one objective against another. That is, no one knows what effect achieving one target may have on other aspects of a hospital's performance.

DGHPSim uses system simulation to represent the main workings of a hospital. It is designed so that it can be configured to fit any specific hospital by using Hospital Episode Statistics (HES) data and other data collected from a hospital's information systems. The HADA tool is used to transform this data into a form used by DGHPSim.