I wonder if you’ve thought about why we are being advised to stay two meters (or six feet) away from other people to avoid Coronavirus transmission? That number used to be half the distance by the way, only changing fairly recently. To understand it, we have to go back to post-World War II England, and to a hospital not terribly far south of Stonehenge.
What we learned in studies like these was that airborne pathogens die quickly when they become an aerosol, and a safe distance was determined at about one meter (three feet). For years that was the guidance we were given, and then came along SARS which was spread far and wide not by vacationing hikers, but by air travel.
Fast forward to today and social-distancing guidance advises us to stay two meters away from other people. Humans are pretty good at judging that distance – it’s about the height of a tall person, the length of a llama, and the widest puddle I’ll venture to jump across. That number becomes critically important when moving beyond social-distancing to contact-tracing however.
Contact tracing is the complex process of backtracking in time to find out who an infected individual may have come into contact with and subsequently transmitted the virus to. If we can do this with a high degree of confidence, then we can accurately predict who is at risk and target limited testing resources. This kind of pinpoint screening is one of the keys to getting back to work.
Technology can track people while they are in high-risk situations and build up a historical record of where they have been. If you could do that for everyone in a factory, for example, if a single person became ill you could quickly go back and identify who should be tested.
Simple then: you track people, determine who came within two meters in the last couple of weeks and there’s your list. Of course, then you have to go back to the people THOSE people came into contact with, and then the third order contacts, then the fourth…. Such is the way of exponentially exploding contact tracing: it’s compound interest writ large.
With any exponentially growing system, the final result is very sensitive to the underlying data: in this case the confidence we have in our two-meter measurements. Imagine a location technology which made mistakes, one in which the position of a person might be measured incorrectly by as much as 50%. Now the two-meter circle looks more like three meters, and that circle has over twice the area, meaning it could encompass over twice the people.
Here is the crux of the problem in an exponentially growing system: if at every step you are mistakenly predicting twice the number of infections, then the answer quickly ramps up to “everyone is sick.” That kind of prediction is of no use at all when the goal is to intelligently allocate limited testing resources.
A location system which can be wrong by up to 50% might sound alarmist, but it is in fact fairly conservative when considering industrial environments. Very large facilities filled with metal machinery and equipment are the worst of all places for wireless tracking systems. In these environments many technologies struggle to achieve accuracy better than three to five times their stated nominal-performance. It’s not unusual to see a system promising one-meter accuracy to regularly deliver results that are five meters or more in error.
At Ubisense we are receiving a constant flow of enquiries asking if we can help with this very problem, and before responding we considered carefully our real-world performance in industrial environments. In this we are more fortunate than others since we have over a decade of global deployments providing analysis data. That data proves that we have the right technology for the job, and we are working very hard to respond to people’s requests with a simple to install solution.
Here’s the bottom line: if we didn’t have a sensor technology designed from the physics-up for high-fidelity performance in industrial environments, if we didn’t have millions of hours of operational run-time under our belts, if we weren’t the leading choice for people-tracking in the exacting discipline of military training, we wouldn’t be offering the solution that we are.
And neither should anybody else.