...As strong as its weakest link

The old proverb, dating at least back to 1786, is nothing but a popular version of a well-established engineering principle. When all elements in a system need to be in perfect condition for the system to work as a whole, any element can single-handedly make the system fail. If all the parts are equally robust, this is not much of a problem, but if one of the elements is particularly prone to failing, it will naturally be the cause of most of the interruptions in the workings of the whole.

To avoid this kind of weaknesses, engineers try to incorporate redundancy in the systems, such as having two distinct paths to bring water to your house so that if one breaks you can still be supplied through the other one. However, implementing redundant systems is expensive, not only because you need to have a clone of the system that can fill in for the main one, but also because you need highly reliable switching systems that can detect a failure in one of the branches, isolate the failure to the failed system and start the backup. Just to give you an example, having one backup car in your garage while you park your main car in your driveway is not a good redundancy system: if your main car fails to start when you go to work in the morning you will not be able to use the other one either, because the first one is blocking its way. In this case, the main car is the single point of failure that can bring your transportation system down.

Photo: PxHere

I have come to thing today about redundancy because I have read on the newspaper that a huge container ship went aground in the Suez canal a few hours ago and maritime traffic will be completely blocked until the vessel is re-floated and moved aside. A whole team of tugboats has been working on it with still little success, so the pile up of ships waiting to cross this major waterway is growing, and the delay is going to have a major impact in many supply chains.

For many years since the industrial revolution, the standard manufacturing practice was to assemble all the materials at the factory before the assembly started so us to ensure that the production could be finished. However, this required the factories to include huge storage facilities to contain both the raw materials used as input and the manufactured goods that had been produced. In post-war Japan, however, this approach did not work because its high population density made the construction of huge factories impractical so instead the introduced the Just-in-time method, where the production was divided in many small factories that only stored the amount of materials currently being worked on. Of course, this required a very tight coordination among the different producers, but if Japanese are good at something it is coordination.

Now this production method has extended throughout the world and many industries are working with lean inventories, fueled by globalization and the advances in logistics, but inadvertently introducing a very strong dependency on the supply chains. As usual, one can build some buffers, temporary storage facilities to account for the irregularities in the supply chain such as having a week's worth of raw materials, so that you can absorb some of the disruptions, but in the end the storage of these supplies is costly so the general trend is to keep them really small.

The good part of keeping the storage small is that it reduces the costs, so the manufacturers can lower their prices. The bad part is that the dependencies on the logistics can lead to disruptions in the supply even to the final consumers, as we have seen with the Toilet Paper Wars at the beginning of the pandemic. And all these dependencies are inherently driven by the high cost that a stronger redundancy would have for the current productive system.

A similarly scary trade-off has been made for many years and essentially across the globe in terms of preparedness for a global pandemic. The American billionaire, philanthropist and former CEO of Microsoft Bill Gates warned about these risks in a TED talk he gave in 2015 on occasion of the Ebola virus outbreak that had been ravaging western Africa for almost one year. He pointed out how lucky we had been with the evolution of the outbreak because the virus was not airborne, the disease was very incapacitating (patients were bedridden within a day or two), and it had never reached big urban areas. But he also warned that a virus like the Spanish flu of 1918 would wreak havoc in the modern world precisely by the reasons that made Ebola easier to control: a disease mild enough that would allow many infectious patients to continue with their daily life, and a virus that can be transmitted through the air. And this is precisely what has happened with SARS-CoV-2.

Gates made the point that preparedness to tackle such an epidemic was key in the same way that it is to tackle war: we keep our armies assembled, trained and equipped so that we do not have to scurry around putting something together in a rush in case anything happens. But, even with the Ebola warning, six years later the COVID-19 has found as ever so unprepared, and we are paying the price.

Luckily, the new vaccine techniques that had been in preparation for years have proven to be applicable to this case (admittedly with a very strong economic booster to help completing the development), so the final toll is very likely to be well below the 30 million deaths of the episode one century ago. Still, it might be worth considering in the future when it is advisable to pay for preparedness and spare ourselves the worst that nature has to offer, because our health systems are, and will continue to be, the weakest link. Have a nice evening.