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22 June 2020 | Story Andre Damons | Photo Anja Aucamp
Herkulaas Combrink.

A lot can be said about forecasting and modelling, its accuracy, and how it works. Forecasting and modelling provide any decision-maker with plausible predictions or outcomes to give some kind of estimated consequence. Without this field of science, planning would be difficult, as one would simply make decisions without knowing what might potentially happen to a specific cohort, market, or product. Forecasting as a concept can be seen as a set of mathematical, statistical and/or computational tools applied to a set of assumptions about something.

This is according to Herkulaas Combrink of the Centre for Teaching and Learning at the University of the Free State (UFS) and PhD candidate in Computer Science at the University of Pretoria (UP), following the South African government’s modelling of how many people would contract COVID-19 and die, which has come under fire in recent times – with one expert saying it was “flawed and illogical and made wild assumptions”. 

Combrink is of the opinion that South Africa – by using the MASHA Consortium – is using the best minds that the country has to offer. The fact that the leadership took a pragmatic stance and reached out to the scientific community has mitigated a medical disaster in a healthcare system that was not ready a few months ago.

“The government is looking at as many models as they can, but is working very closely with MASHA and the CSIR” says Combrink, who has been involved in clinical surveillance, and also forms part of the modelling team during his secondment to the Free State Department of Health. 

Prof Shabhir Madhi, the former head of the SA National Institute for Communicable Diseases (NICD), recently said that the initial modelling and fatality estimates were “back-of-envelope calculations”.

According to a news report, the government’s initial model also predicted that 600 COVID-19 patients would need treatment in intensive care units (ICU) in SA by April 1. But by April 18, the last publicly released figures showed that there were 32 COVID-19 patients in ICU.

Tried-and-tested models
The models currently used are tried-and-tested epidemiological models, mathematical models, and economic forecasting models that have been used in the past. It has now been calibrated to the specifications that we know of this disease, which come from publications. The reason why you would use more than one model is to compare models retrospectively, so that you can see what is going on.

“The government immediately reached out to the best minds in the country, and with the aid of the consortium, took a stance to throw scenarios at the different models and stress test them so that they could know that they are using the best possible models to assist in resource management and decision-making. If government responded in a different way and didn’t reach out, we might not have had a lockdown and subsequently would probably have been in a different position where the country wouldn’t be ready.” 

“We can say with a high degree of confidence that the lockdown really helps to ease and flatten the curve in the country. In light of flattening the curve, the right decisions have been made,” says Combrink.

COVID-19 still new
Unfortunately, says Combrink, during the COVID-19 pandemic, there was not enough information related to the disease assumptions and it lacked the rigour and perfection associated with the already existing prediction models. Although it may feel like a lifetime, the first COVID-19 case was only reported in December 2019. Add to this that not all the parameters related to the disease were known in January, it was challenging to determine all the ‘ins and outs’ of this disease. 

“Luckily, the mathematics and statistics of an outbreak have been extensively studied, and as a result, we only needed to use the correct parameters to estimate the spread of the disease in some of the outbreak models. The Minister of Health, Dr Zweli Mkhize, and the national modellers led by Dr Harry Moultrie, were transparent with not only their projections, but also how they derived their conclusions and what parameters they used,” says Combrink.

The most important thing in modelling is to calibrate according to what is known about the disease and people, explains Combrink. “It is impossible to predict people and a disease100% accurately, because you don’t always know how a virus will react to every single person’s body and you can’t predict human behaviour.” 

“So, there is a certain degree of error and a certain degree of confidence that lies within each model, and that is why you evaluate these models on a regular basis. And this is important. You will never be able to say this is the exact number. Just like the weather. If the weather patterns were predicted to be 12 degrees tomorrow, and it turns out to be 16 degrees, you at least packed a jersey. You knew it was going to be cold. The chances that the weather predicts that it will be 12 and it turns out to be 57 degrees, is virtually zero. It gives you more or less an indication what to prepare for

Models are useful, but can also be wrong
Combrink says if you want to apply any model, you need to understand the assumptions and the limitations of the models. Given a certain set of criteria – what are the assumptions you are making and what are the expected outcomes – you can only act according to that. He says, as time goes by, we can now see that there are some models that yield much better results because we can now compare what was predicted two months ago and what is actually happening. 
 “Some models are useful. We can get a better understanding of the pandemic’s possible trajectories or gain an understanding of the impact that different interventions have made. Models are used for decision-making. These decision-making strategies can save lives. That is the purpose of models and modelling during these times.”

Combrink uses the weather forecast to explain how modelling works and that models can be wrong. “Yes, models are wrong all the time. Take the concept of weather as an example. How many times has the weather forecast predicted that there is an 80% chance of rain, and then it doesn’t rain? Models can give you a certain degree of confidence in an outcome related to a specific event or scenario, so that you, with some degree of confidence, can go forth and plan accordingly.” 

“However, models can’t tell you what exactly will happen tomorrow, or the day after. It is not a crystal ball, and it is not a mirror into the future, but it can give you an indication of what is likely possible related to a specific scenario if you used the right variables. Let us consider that there is an 80% chance of rain in the weather forecast; will you a) go to work without an umbrella or b) with an umbrella? If it doesn’t rain, you are at least prepared for the rain because you took your umbrella. If you didn’t take the umbrella and it does rain, you may run into trouble because you did not appreciate the warning of the weather forecast. I think it is this concept that makes modelling so powerful. You can use it as a tool to prepare for things, in the event that it does happen, with a certain degree of confidence. Just like the previous example, there is also a 20% chance that it might not rain, but wouldn’t you want to be prepared?” explains Combrink. 
 
Models are tools that can be used to base decisions on
No one truly knows how the pandemic will play out, and according to Combrink, it can be said with a high degree of confidence that if nothing is done about the pandemic, we know how it would turn out from a healthcare perspective. 
“If you look at some of the global projections they gave months ago (in January and February) and compare it to what they said for March and April, you can see that they predicted, with a fairly good degree of confidence, what actually happened in certain countries. We have a good idea in terms of numbers and how it will play out, but what we will never know is what the impact will be on the socio-economic status of a person, the economy, and the impact on other diseases.”

“We do not know what is going to happen when it comes to mental health and COVID-19, for example. This is why modelling is a multidimensional approach, requiring inputs from various fields. Models can help us in the same way the weather forecast does. It is a tool that we can use to base certain decisions on, to be more prepared, because without it we won’t know to pack an ‘umbrella’ if it is predicted to rain or pack a ‘jersey’ if it is projected to cool down.”

News Archive

Media: ANC can learn a lesson from Moshoeshoe
2006-05-20


27/05/2006 20:32 - (SA) 
ANC can learn a lesson from Moshoeshoe
ON 2004, the University of the Free State turned 100 years old. As part of its centenary celebrations, the idea of the Moshoeshoe Memorial Lecture was mooted as part of another idea: to promote the study of the meaning of Moshoeshoe.

This lecture comes at a critical point in South Africa's still-new democracy. There are indications that the value of public engagement that Moshoeshoe prized highly through his lipitso [community gatherings], and now also a prized feature in our democracy, may be under serious threat. It is for this reason that I would like to dedicate this lecture to all those in our country and elsewhere who daily or weekly, or however frequently, have had the courage to express their considered opinions on pressing matters facing our society. They may be columnists, editors, commentators, artists of all kinds, academics and writers of letters to the editor, non-violent protesters with their placards and cartoonists who put a mirror in front of our eyes.

There is a remarkable story of how Moshoeshoe dealt with Mzilikazi, the aggressor who attacked Thaba Bosiu and failed. So when Mzilikazi retreated from Thaba Bosiu with a bruised ego after failing to take over the mountain, Moshoeshoe, in an unexpected turn of events, sent him cattle to return home bruised but grateful for the generosity of a victorious target of his aggression. At least he would not starve along the way. It was a devastating act of magnanimity which signalled a phenomenal role change.

"If only you had asked," Moshoeshoe seemed to be saying, "I could have given you some cattle. Have them anyway."

It was impossible for Mzilikazi not to have felt ashamed. At the same time, he could still present himself to his people as one who was so feared that even in defeat he was given cattle. At any rate, he never returned.

I look at our situation in South Africa and find that the wisdom of Moshoeshoe's method produced one of the defining moments that led to South Africa's momentous transition to democracy. Part of Nelson Mandela's legacy is precisely this: what I have called counter-intuitive leadership and the immense possibilities it offers for re-imagining whole societies.

A number of events in the past 12 months have made me wonder whether we are faced with a new situation that may have arisen. An increasing number of highly intelligent, sensitive and highly committed South Africans across the class, racial and cultural spectrum confess to feeling uncertain and vulnerable as never before since 1994. When indomitable optimists confess to having a sense of things unhinging, the misery of anxiety spreads. It must have something to do with an accumulation of events that convey the sense of impending implosion. It is the sense that events are spiralling out of control and no one among the leadership of the country seems to have a handle on things.

I should mention the one event that has dominated the national scene continuously for many months now. It is, of course, the trying events around the recent trial and acquittal of Jacob Zuma. The aftermath continues to dominate the news and public discourse. What, really, have we learnt or are learning from it all? It is probably too early to tell. Yet the drama seems far from over, promising to keep us all without relief, and in a state of anguish. It seems poised to reveal more faultlines in our national life than answers and solutions.

We need a mechanism that will affirm the different positions of the contestants validating their honesty in a way that will give the public confidence that real solutions are possible. It is this kind of openness, which never comes easily, that leads to breakthrough solutions, of the kind Moshoeshoe's wisdom symbolises.

Who will take this courageous step? What is clear is that a complex democracy like South Africa's cannot survive a single authority. Only multiple authorities within a constitutional framework have a real chance. I want to press this matter further.

Could it be that part of the problem is that we are unable to deal with the notion of "opposition". We are horrified that any of us could become "the opposition". In reality, it is time we began to anticipate the arrival of a moment when there was no longer a single [overwhelmingly] dominant political force as is currently the case. Such is the course of change. The measure of the maturity of the current political environment will be in how it can create conditions that anticipate that moment rather than ones that seek to prevent it. This is the formidable challenge of a popular post-apartheid political movement.

Can it conceptually anticipate a future when it is no longer overwhelmingly in control, in the form in which it currently is and resist, counter-intuitively, the temptation to prevent such an eventuality? Successfully resisting such an option would enable its current vision and its ultimate legacy to our country to manifest itself in different articulations of itself, which then contend for social influence.

In this way, the vision never really dies, it simply evolves into higher, more complex forms of itself. If the resulting versions are what is called "the opposition" that should not be such a bad thing - unless we want to invent another name for it. The image of flying ants going off to start other similar settlements is not so inappropriate.

I do not wish to suggest that the nuptial flights of the alliance partners are about to occur: only that it is a mark of leadership foresight to anticipate them conceptually. Any political movement that has visions of itself as a perpetual entity should look at the compelling evidence of history. Few have survived those defining moments when they should have been more elastic, and that because they were not, did not live to see the next day.

I believe we may have reached a moment not fundamentally different from the sobering, yet uplifting and vision-making, nation-building realities that led to Kempton Park in the early 1990s. The difference between then and now is that the black majority is not facing white compatriots across the negotiating table. Rather, it is facing itself: perhaps really for the first time since 1994. It is not a time for repeating old platitudes. Could we apply to ourselves the same degree of inventiveness and rigorous negotiation we displayed up to the adoption or our Constitution?

Morena Moshoeshoe faced similarly formative challenges. He seems to have been a great listener. No problem was too insignificant that it could not be addressed. He seems to have networked actively across the spectrum of society. He seems to have kept a close eye on the world beyond Lesotho, forming strong friendships and alliances, weighing his options constantly. He seems to have had patience and forbearance. He had tons of data before him before he could propose the unexpected. He tells us across the years that moments of renewal demand no less.

  • This is an editied version of the inaugural Moshoeshoe Memorial Lecture presented by Univeristy of Cape Town vice-chancellor Professor Ndebele at the University of the Free State on Thursday. Perspectives on Leadership Challenges In South Africa

 

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