Our government officials and health experts have kept saying this in the past few days! Do they really know what they are talking about? Obviously not! Or they only meant to exaggerate the situation to justify the implementation of more drastic measures to support our nationwide zero-covid policy. This could be good for Hong Kong, but the abuse of mathematical terms is not acceptable or truthful, coming from our top officials and medical experts. Looking at it differently, this may simply reflect how ignorant of mathematics these people are!
Geometric progression, a secondary school math concept, means a sequence of numbers successively being kept multiplied by a fixed constant, like 1, 4, 16, 64, 256, 1024, and so on. This is a very aggressive progression! Think about it! If Omicron is indeed spreading in such a progression in Hong Kong, we should be heading to tens of thousands by now. The so-called reproduction number R0, which is used by medical professionals to indicate the contagiousness of a disease, is the number of people possibly infected from a single carrier. With no refinement, direct application of this R0 could indeed end up with the conclusion of a geometric progression with the multiplying factor being R0. If R0 = 4 for Omicron, then we should expect a progression to look like 1, 4, 16, 64, 256, 1024, 4096, 16384, 65536, ... and blowing up in a short time!
(Chart added March 5)
The truth is that spreading dynamics is nothing like this, definitely not a R0 geometric progression! It is rather governed by a dynamical process, where the rate of change of the infected number is a function of the current infected number and susceptible population size, of course with a whole bunch of parameters like infection rate (how fast the virus can spread), recovery rate, and other factors such as non-pharmaceutical interventions that suppress transmission. Technically the so-called compartmental model (commonly called SIR or SEIR in epidemiology research) is a set of differential equations describing the spreading progression, and with data generating the controlling parameters, the model can accurately track the progression. In short, it is never like a geometric progression!Hong Kong's top officials are mostly trained with a political, art or social science background. They could be extremely sensitive and careful selecting the right words when making a political announcement, but can be completely flexible or imprecise when coming to the use of mathematical jargons.
A more outrageous example of math abuse is 'dynamic zero infection' (動態清零). The term 'dynamic' refers to variation with time. 'Zero infection' is a state of having no infection. That's clear! But 'dynamic zero infection' is a self-contradictory term. None of our top officials could explain what it actually means. Even our CE said publicly that she was not in a position to explain it as she was not the initiator (literally 我唔係始作俑者！). They all knew they could not achieve zero infection, and they all knew Beijing wouldn't like to hear the truth which is 'sometimes zero, and sometimes not zero', and so adopting the term the mainland experts invented is the only politically wise choice. The same usage can be extended to anything that the government can't do or does poorly but wouldn't like to admit.
The lesson is: when you can't find a good way to lie about your failure and you still want to lie, simply say you have made a 'dynamic' success.
February 8, 2022
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