R0, the Messy Metric That May Soon Shape Our Lives, Explained

from NYTs

World leaders and public health experts are poised to spend the coming months or years obsessed with a variable known as R0.

Pronounced “R-naught,” it represents the number of new infections estimated to stem from a single case.

In other words, if R0 is 2.5, then one person with the disease is expected to infect, on average, 2.5 others.

An R0 below 1 suggests that the number of cases is shrinking, possibly allowing societies to open back up. An R0 above 1 indicates that the number of cases is growing, perhaps necessitating renewed lockdowns or other measures.

But R0 is messier than it might look. It is built on hard science, forensic investigation, complex mathematical models — and often a good deal of guesswork. It can vary radically from place to place and day to day, pushed up or down by local conditions and human behavior.

Yet for all its vagaries, R0 is expected to shape our world in the coming months and possibly years as governments and health experts treat it as the closest thing to a compass in navigating the pandemic.

What follows is a simple guide to how this metric works, why it matters and how to think about it.

More here.

Posted in Healthcare, Science and tagged , , .


  1. Astonishingly, this little metric will be determining how society will be run in the near future for who knows how long. Experts say that R0 is “easily misrepresented, misinterpreted, and misapplied.” This means that it is not always right and it could lead us to do the wrong thing if not looked at correctly. The only problem is that this is the closet thing that we have that can sort of lead us in a direction out of this mess. The current outbreak that is occurring is something that we have never seen before. No one has experienced or gone through something like this that knows exactly what we need to do. There is no one clear cut answer that we can all use. This is causing many to come up with their own ideas and that is what is causing all the arguing because people can not stand for people to tell them that their idea will not work. It provides an excuse to use for whatever they choose to do so if the number is down, they start to ease back on the restrictions and say that this R0 number is the reason why and if they want to tighten restrictions then they will say that the R0 is high or rose.
    The R0 is going to be used as a way to show people that certain actions that are being taken are the right ones so everyone just stops their complaining and actually starts to comply with the motions that are being taken to combat the disease. Who knows, social distancing could have beaten the disease if everyone complied with the idea of it, but people could not be bothered to change their daily routine and now here we are a few weeks later and we are still dealing with the disease.

  2. R0 is a very cool idea, but it will not shape society for the future in its current form. It is clearly not extremely reliable as the article says, a lot of the model lies in guesswork and this is not ideal if you are trying to put a metric out there. I do think that it is among the best we can do at the current time, but technology is advancing at a quickening pace. The future will bring more reliable predictive models that will allow officials to make much better informed decisions. In the current pandemic, the models were quite a bit off from the actual infection rate, even when accounting social distancing. Now in no way am I saying that we should not be social distancing, because it is one of the reasons that the infection rates did stay as low as they did, and it likely saved tens of thousands of lives. But, the point is that the models can be improved.

    Baseball is a sport that is centered around metrics that drive decisions all the way from the field to the offices of the General Manager and CEO. This was not always the case, and I think that society and baseball can follow a sort of similar path. Baseball, in its early days, was played and managed by concepts. Score runs and do not allow runs were the two main goals. This evolved into keeping batting average (AVG), on base percentage (OBP), slugging percentage (SLG), earned run average (ERA), and walks/hits per inning pitched (WHIP). This was not the end of baseball’s Sabermetrics. Those metrics evolved into more advanced metrics such as weighted OPS which added AVG, OBP, and SLG to make a better hitting metric. Today metrics like wOBA, BABIP, ERA+, ISO, and WAR dominate decision making. This is because they do a better job at predicting what sort of production a player can bring. Society is around the third step, where we are using basic stats to create better metrics, but there is still another leap to be made that can better predict pandemic models.

  3. This is a topic that will be talked about for a very long time. This was not the first time I’ve heard of R0, and it will definitely not be the last one. The system that relies on educated guesses will improve dramatically in the next few years just because of the pandemic and how awfully it has affected the whole globe, but as of right now, it is not too reliable, and the smallest errors in the system can easily change the whole vibe of the situation. Also, with a disease as COVID-19, it is very difficult to keep track, as there might be millions of people who have been infected, but they just have not had symptoms. Until we can monitor everyone’s health, or at least know everyone who gets infected, the whole R0 system will stay on guesswork. With the recent development of science and medicine, I don’t think it is far away that we will be able to monitor at least almost everyone’s health, but this will raise another question about privacy. If the government could see if you’re infected through a machine, many people might not like it, as it would feel like someone is taking away our privacy. All I can do is wait and see how the future will mold

  4. At first, I was confused as to what the title and in particular NYT’s article meant about the variable R0 (also known as the “basic reproduction number”). After delving further I realized that R0 is pronounced “R-naught” and it estimated the number of new infections from that one variable. The R0 for Covid-19 is 2.5 meaning an infected person will infect an average of about 2.5 people.

    This isn’t the first time I have encountered the concept of R0 as I have previously learned about it in Vox’s Youtube video “Coronavirus is not the flu. It’s worse” (https://www.youtube.com/watch?v=FVIGhz3uwuQ). Believe it or not, the concept of R0 is behind all the procedures that have been implemented to stop the spread of Covid-19; social distancing and lockdowns. As I said previously the R0 for Covid-19 is around 2-2.5 where after 10 generations of infections, one person can end up infecting more than 2000 people. So obviously the smaller the R0 the better because as long as it’s under one, one person will infect at most one person and therefore future infections will decrease and will be successively smaller than the last.

    As we all know that Covid-19 is a new virus in the family Coronavirus (the same family as SARS and MERS) so there are no treatments or vaccines for the virus. Unlike the flu where many Americans are immunized, Covid-19 is not and therefore everyone on the planet is susceptible to becoming infected. By understanding R0 and therefore analyzing who (people or communities) will likely be infected, proper lockdown procedures, as well as social distancing, is critical yet more effective in preventing more infections as there are no immunized people acting as “barriers” to prevent or curb those who are infected from infecting others and therefore decreasing R0.

  5. 16. I would not be surprised if the word R0 (pronounced R-naught) became part of regular vocabulary in the near future. With the unprecedented times we are facing right now, there are a lot of words that have become an everyday part of my vocabulary that I wish were not like “death-rate”. Initially, I was thinking that knowing this number could provide a much easier way to see what is going on with this pandemic and the signs that it might be getting better or worse. However, it proves to be a lot more complicated and requires a lot more guesswork than one would think. I was genuinely shocked to read that the R0 for measles ranged from 3.7 to 103, which is obviously a very big difference. However, despite the trickiness in estimating it, it can be a very useful tool for the researchers trying to understand it and the officials trying to manage it. The importance of it was very easily shown in how the article explains that having an R0 of 1 can be managed in Germany, but the German chancellor felt that if it increases to 1.1, their healthcare system will probably be overwhelmed. One of the biggest takeaways from this article is that this number can be controlled by people. The more people go out and risk getting infected, the higher the R0 will be because the disease will be spreading to more people. If people practice social distancing, the expectation is that R0 will decrease because if someone has the coronavirus hopefully they are staying home, and even if they are not, they should not be coming into contact with as many people when they do go out in public.

  6. The Coronavirus has been severely impacting the world since the start of 2020. It seems that some states are trying to reopen their economies as of late which is understandable because of the increase of unemployment but cannot be a good idea if that means the exponential increase of new COVID-19 infections. R0 s used to measure this. R0 t is a complex scientific method to conduct an analysis of how many people an infected person might infect in the course of their infection. If the R0 is smaller than 1 it suggests that the disease is decreasing, although if the R0 is greater than 1 suggests that the disease is increasing. So, if the R0 is more than one then that means that states will need to continue to enforce quarantine protocols to reduce the number of cases occurring. Many European countries are currently reporting an R0 of less than 1 but as we have seen in the last few months, the rate of infection for COVID-19 can volatile. If states were to reopen and the R0 suddenly increased to a number greater than 1, then it would be detrimental to the population of that state. The United States and most of the countries of Europe are trying to figure out to help each other get better estimates for their R0, so they don’t reopen to quickly and also so they can manage their option for reopening their economies.

  7. COVID-19 has had a massive impact on the modern world. More than thirty million Americans have lost their jobs, oil prices have crashed into the negative range, and the stock market is more turbulent than ever. This virus will cause changes throughout the world that will last for many years to come. The preventive measures, though useful in reducing the spread of the virus, has had a negative impact on the economic well-being of many across the global. Some public officials throughout the world are preparing to reopen their nations, territories, and municipalities after long, and in certain cases, not so long quarantine. The questions that one has for all of this is if these public officials are making the correct decision with reopening their nations and such up for a return to normalcy, and if their decisions are wrong, when is it right to end the preventive measures put in place.

    It has been shown that the world has a log time before a viable vaccine is developed and available for the public. So, one would think that it would only make sense to wait until a vaccine is developed, but with the economic troubles caused by the pandemic will only get worse as time goes on. This makes it clear that countries will have to reopen to some extent before we have a vaccine available. Some countries such as China and South Korea have already reopened to some extent, though it should be note that China has had to reinstate some measures afterwards due to a possible second wave of the virus, which shows just how difficult it can be to determine if the situation in a given area is safe enough to rollback preventive measures. Thus, we should be careful in determining if the virus has burned out of a given population.

    Some people in the United States have started to protest for their state government to lift quarantine measures in their state. Some of these protesters are doing this due to economic damages done to them personally, due to the effects of the virus, other don’t believe in it, argue that 5G is involved in it, and other have more simplistic reasons, such as the protesters who wanted a haircut. Some governs have responded by reopening up their states or otherwise preparing to reopen up their states. Given the previously mentioned information about the troubles that China has had with reopening, it seem that both protesters and the politicians that espouse ending preventive measures or otherwise are in the process of ending them, have not taken into consideration of the effects that removing these measures will. Many of the states that are reopening were some of the last to impose the health measures they seek to end. This are behind on the infection cycle that other states such as New York and New Jersey are on. States that are reopening are endangering their citizens, for it is likely that such an infectious virus as COVID-19 exists in their areas, and as shown will lead to a second wave of infections, as cares of the virus leave their homes and enter back into the public.

    With all that had been said, I think we are far away from being able to reopen society, and even if we do, that doesn’t mean that we are out of the clear. This virus and the measures that have been used to stop it ha had a negative effect on the economic well-being on many in the world, but that doesn’t mean that we should just end the health measures in place. We still have some work to do before it is safe to return to normal, and those who seek to end the response to the pandemic now, will only cause it to last longer.




  8. I remember when this figure started getting rolled out for the novel Coronavirus, and it wasn’t confusing but was very bound to guesswork. After all, no one outside of China can measure exactly where and what most people do and who they interact with. The original numbers for Coronavirus were between 4-8 infected per 1 infection, with some estimates as high as 13 and some super-spreaders giving it to hundreds by living their lives and riding a bus or subway. However, finding this R0 and getting a mean rate of infections can go a long way, as the article describes. It doesn’t matter if this is 100% correct, what matters is that it gives us a better indication than what we would have otherwise when it comes to successfully opening society back up after a pandemic-caused lock down. Something important to consider, however, is how volatile this number is. Once it passes 1, it will go up exponentially as the mean will be impacted by every 1 person who gives it to multiple people. This is especially true and concerning when considering a disturbingly contagious pandemic/disease/virus/etc like the novel Coronavirus. Think of it like a curve (a.k.a. flatten the curve), There starts with a flat point that very slowly rises, then immediately and uncontrollably rises unless drastic measures are taken to stop it. If it gets re-released before it hits zero (or the R0 factor greater than 1) the curve will come back. While the R0 is not exact or purpose, it seems to be the best measure that we have.

  9. R-0 is an interesting metric which estimates the amount of new infections which originate with a single case. It is an essential metric for understanding when cases are being minimized effectively, and will help show when we have successfully “flattened the curve.” Unfortunately, the metric seems to rely heavily on guesswork, which may lead to some inaccuracies in the future. Nonetheless, the metric still helps us understand how this pandemic is effecting others and how to manage the situation efficiently. Covid-19 has been calculate to have and R-0 of about 2-2.5 and a serial interval of 4-4.5 days. I believe that R-0 is a metric that we should remain interested in and develop until we can produce the most reliable numbers possible, because the benefit of being able to accurately predict the infection rate of a new illness with minimal sickness is exponentially greater than estimations. I think the government use of this metric going forward can severely reduce the impact of plagues which threaten millions of lives like the Coronavirus did. The website attached to the articles estimates the R0 of each state and that accounts for rate of transmission, to which a majority of the states are below 1. This is important because it shows that they somewhat stopped the spread of the virus. It will be exciting to see how governments utilize this metric moving forward in a way that will handle outbreak like the one we are seeing right now. I hope that we can drive our national R0 as low as some European countries which have seen dramatic shifts in the numbers and demonstrated that they definitely have the capabilities to handle an international pandemic. Our R0 being higher than other countries shows me that my suspicions that the country has not reacted to the onset of Coronavirus well are confirmed. Not properly social distancing and not prioritizing the safety of the people has been devastating to the United States citizens, and I hope that we can learn from these mistakes to have a bipartisan effort to eliminate the threat caused by these horrible illnesses.

  10. When it comes to issues like coronavirus, certain metrics and numbers become more important and taken as more of fact than they really are during times of turmoil. This metric is allegedly supposed to be shaping our lives in the coming months and years, however its basis is speculation. It relies on many assumptions and can vary from township to township, which means it is not a consistent metric by which to assume how we should treat the virus. Many governments are looking at this metric as they look to reopen their economies as quickly as possible, its important to realize that these metrics are meant as ways to estimate and further analyze a situation, not the sole proponent that determines its severity. Many follow random metrics and numbers in attempts to justify their own views, and in this case many people want the economy reopened as soon as possible. This article seems to focus on this R0 metric, but as much as it seems like useful tool to help in analyzing trends in infections and predicting aspects of the pandemic, it is in no way as important as people are making it seem. This number only predicts how many people will get sick from a certain group size already sick. Higher numbers means higher infection rate, but does not take into account deaths, and relies on many guesses. This makes its vary depending on who uses it, and also where it is used, which means it can not be used as a metric across multiple areas. It seems like the mainstream has made this metric much more important than it truly is, due to misinformation and a general uneducated public that will look for easy crutches to get them through the panic. These metrics are definitely important for skilled researchers and analysts as tools, but are in no way the most important factor in determining what to do in the future.

  11. Some people may be saying that quarantine is working and people’s lives are starting to get put back together as the infection rates drop but when taking a closer look it becomes obvious that RO which is the infection rate is not as black and white as it seems, there is infact a grey area. After looking into this matter and reading this article I found that R0 is messier than it might look. Although this ideology is built on top of hard science, all types of different conclusive forensic investigation, and the very thorough mathematical model and a lot of educated guesses. Due to the nature of this model it is very easy for the numbers to be very drastically different day to day and in fact cause the numbers from one day to be reliable when used two or three days later. Although this number is messy it is very, very important to keep up on the corona virus and the amount of people infected so that states can make decisions based on the feedback that they are getting from the RO numbers so that they can do their best to keep innocent civilians safe. Although it may seem random the term is in fact borrowed from the study of demographics and it uses birthdays and age to figure its calculations.
    R refers to reproduction and 0 to the zeroth generation, as in patient zero. When these two variables are combined a lot of people will say that these numbers are in fact a byproduct number. The RO number is calculated from innate features of a disease, like how easily it jumps from one person to the next, along with elements of humans. The serial interval is more fluid than the other numbers and for that reason very People can heavily influence R0, which is why it receives so much more attention than other metrics. Overall, I feel that it is vital for Americans to make the right decision and pay close attention to the trend that is happening and the infection rate and how they are controlling the number of individuals affected. If people pay attention to the amount of people that have been infected and follow the social distancing guidelines then it will be more likley that the RO number will come down from its peak and that in the end it will overall stabalize making it a more reliable number. I feel that people in America have not taken this maner seriously because the infection rate still has not been stabalized. I think that the states are not going to be ready to open by may 15th because the infection rate still is not stable and if they open up the states and attempt to move back into normal daily activities it will cause the infection rate to spark back up again reversing all of the percautions taken in order to stop the original infection, initiating the second wave.

  12. I believe that R0 is already an important factor in everyone’s lives moving forward. According to Khan Academy (https://www.khanacademy.org/science/health-and-medicine/current-issues-in-health-and-medicine/ebola-outbreak/v/understanding-r-nought), R0 is the ‘number of new cases that an existing case generates on average over the infectious period in a susceptible population. The way it’s calculated is fairly simple but has multiple derivatives. The one the article uses is the number of new cases divided by existing cases but a paper from Stanford uses a different formula (https://web.stanford.edu/~jhj1/teachingdocs/Jones-on-R0.pdf). A video on the YouTube channel Trefor Bazett (https://www.youtube.com/watch?v=Qrp40ck3WpI) explains the SIRS Model. This video uses a different formula: R0 is transmission rate times the susceptible population divided by recovery rate. The point is that R0 can be calculated under several different types of logic. Each one tells a different picture of how quickly a disease or virus can spread. Because of this, we can get a different perspective on various aspects of an epidemic or pandemic. While yes, R0 is only a statistic number and may not be the best model, statistics are truly given valid meaning when put under context. R0 generally does not naturally skyrocket up or dramatically fall. Policies such as social distancing and lockdown and individual actions are what causes those changes. By using R0 in conjunction with other indicators and timelines, it becomes an indispensable tool for analysts.

  13. I found Max Fisher’s article on R0 very interesting. The idea could be a great way to analyze the liveliness and the threat level of viruses. COVID-19 having a 2.5 R0 is an example of a disease that should be taken seriously due to the rate at which it infects others. As the article points out, when the R0 of COVID-19 is below one, we will know that the virus is on the decline and we are moving in the right direction. Unfortunately, R0 is a bit too good to be true right now. Fisher states, “It is built on hard science, forensic investigation, complex mathematical models – and often a good deal of guesswork.” The science and the math models have an opportunity to be great, but the fact that the math models are based on educated guesses, leads to possible incorrect results. I do not think that this program is advanced enough to be used for COVID-19. Many believe that R0 is easy to apply the wrong way and misinterpreted. The model is still incredibly inconsistent as pointed out in the article when Fisher talks about measles having an R0 of 3.7 to 203. R0 is simply not consistent enough or advanced enough to be used to properly gauge the severity of a disease. However, at this point in time it is one of the only resources that we have to judge COVID-19 and therefore is a valuable asset. I think R0 is a great idea to judge whether or not their policies for the virus are working. If the R0 is down, then more things can be opened and then reassessed when the next R0 report comes out.
    Although R0 is not accurate in 2020, in a few years the program has the opportunity to be incredibly useful. If the system becomes more accurate, which I believe it will as time goes on, it can help governments make decisions regarding pandemics, diseases, or viruses in general. If officials know the virus is on the decline, they may be able to be more aggressive with opening up places to the public. The COVID-19 pandemic is just going to increase the rate at which technology involving R0 is researched and progressed. With COVID-19 still impacting our lives, the funding for R0 will continue to be high. This increased attention given to R0 will only lessen the time it takes for R0 to be reliable. As time goes on and technology evolves, this could become a staple for health experts and government officials.

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