COVID Graphs

Predictions of covid19 are always welcome. Being the advocate’s devil (devil’s advocate) I could say: producing graphs is something everybody can do. If you want I could give you 100 other predictions (and with some chance I might be right for some of them). What is really important is the model behind it. Once the model is understood and seen to be applicable to the local situation, the numerics and the graphs are easy to get. Then comes the interpretation of the model and of its consequences. Important is to understand that most models use the assumption that no new measures are taken (measures that are supposed to be taken such as vaccinations must be incorporated in the model or in its simulations). When really new things happen, the models lose their applicability. Example was the Club of Rome predictions (made end of the 60’s). None of the predictions turned out to be correct and some economists saw this as a criticism. Of course — and maybe because of the Club of Rome’s influence — the attitude changes, the economic behaviour changed, the circumstances changed (politically triggered oil crisis of the 70’s) … But in my view the predictions of the Club of Rome had a merit:  if we do nothing a catastrophe will come. The same with covid19 predictions.

The following is not analogous but it is something I have seen (and the data worked!!). To model longevity people try to make forecasts of the mortality. So today they use e.g. the mortality of 65-year old people. Then they use some model to see how the mortality of 65-year people will evolve in the future. This gives rise to "gliding tables”. I have seen models and when applied to REAL data the outcome was a negative mortality in the range of 95==\infty. That means at a later date there are 100 persons 95-year old, the next year there will be 102 persons of 96-year old. A miracle. Extrapolations must be handled with care and a discussion of the model is very important (before applying it). Does the model reflect what we know? Is the model consistent with trivial facts (not fake news)? …

To be Continued (by Chitro MAJUMDAR; 1st December 2020)...