This website makes available a Covid Epidemic Projection model. There is no charge for the model. It was built with the intention that in due course, after appropriate scrutiny, it would be available for use in low and middle income countries. It has not yet had any scrutiny or review by others. Before it is used in any decision making it should be very carefully tested and evaluated. The model has been built using Microsoft’s Excel (as this software is widely used and available) and it therefore requires a computer with this software to run it.
The model takes public historic data about new infections and deaths in an epidemic and provides a simple visual/graphical way of determining an exponential growth of the epidemic. It can make allowance for past and possible future changes in the growth rate. Using the growth rate determined by the user it can give projections of future new infections, plus related hospital admissions.
This model makes projections, not predictions. This looks a subtle difference but it is not and it is extremely important to understand the difference. Predictions are a statement of what will happen in the future. Projections are just calculations that say, if one makes certain assumptions, then calculations indicate other figures as a result. If the assumptions are not correct the projections will not be. So it is vitally important to understand all the limitations and possible errors in the calculations and the assumptions. However, even if some of the assumptions are wrong – and some certainly will be – it does not mean the model is of no use at all, far from it. Its aim is to be useful in rapidly completing the myriad of calculations necessary to relate the raw data to a possible growth rate in an epidemic. A more detailed description of some of the assumptions and limitations is set out in the Limitations page.
A paper on the model has just been submitted for publication on medRxiv. This is not a peer-reviewed journal. It is intended to submit the paper for publication in a peer-reviewed journal soon and the model should not be used until a paper has been published in a peer-reviewed journal. The model itself includes a brief explanation of it and instructions for using it. Further instructions and information are available in the Help page. Information on the legal basis on which the model is made available is also set out in the Legal page. To download a copy of the model, having read all these pages, go to the Download page.