Model overview
The Non-Elective Flow Simulation is an open-source discrete-event simulation developed by Helena Robinson at Countess of Chester Hospital NHS Foundation Trust. It represents patients moving from the emergency department into SDEC or an inpatient bed and explores how bed capacity, admitted length of stay and SDEC activity affect queues and waiting times. The model is written in Python using SimPy and includes a Streamlit interface.
Session objectives and outline
This session will consider whether participants understand the model well enough to reuse it. Participants will:
- describe how they think the model is structured from inputs through to outputs;
- compare that understanding with the repository and SimPy implementation;
- identify how patients, queues, resources and events are represented;
- locate assumptions for arrivals, length of stay, capacity and SDEC activity;
- discuss what they would change for a different question, service or local setting;
- trace a selected input assumption through the model to its effect on outputs; and
- identify how a change would need to be tested, validated and documented.
The aim is for participants to be able to identify an input assumption they would change, locate it in the model and assess whether they understand the implementation well enough to make the change confidently.
Actions for participants before the session
- Retain the working environment and editable repository from Session 1.
- If you did not attend Session 1, confirm that you can complete a model run before this session.
- Consider one assumption or feature you would change for your own service or analytical question.
Additional resources
- GitHub repository — source code and repository documentation.
- Project presentation slides — background to the model and its intended use.
- HSMA showcase presentation — recorded project presentation.
- Vidigi paper — related work on animated visualisation of discrete-event simulation models, using this model as an application example.
The project is documented through its repository and HSMA materials. We are not currently aware of a dedicated peer-reviewed paper or independent reproduction of this specific model.