One more 'til one more...

The phrase "One more 'til one more" has become the unofficial motto of the girls cross country program at Dublin Coffman High School. It started a number of years ago as a way for athletes to motivate teammates in a workout. Everyone can smile and gut it out for the last interval in a workout under normal circumstances. This was an attempt to be recursive and push that little mental boost back one in the workout, letting it give you a little laugh before the second to last interval. Some kids used it this morning during a workout, and it was a powerful reminder, no matter how different practices now (and meets will) look, there is a certain power in the collective effort of a workout. The sense of shared suffering and shared accomplishment is part of what makes most sports, but cross country in particular, worth the effort. 

This has been a weird season. Usually most of the summer is spent with the kids getting together on their own to run every day. This summer it was groups of at most 9 kids arriving at their designated start time, having done a temperature and symptoms check ahead of time. Masks are worn until the warm ups are completed and the kids head out on their run or start their interval workout. As soon as they return, masks are back on. Our groups are being as strictly enforced as we can, which has made it hard to generate the same sense of camaraderie as a normal season. Groups arrive at staggered times so that we don't overcrowd the available space. With 92 boys and 48 girls, things can be crowded even when we are broken into groups. But we are soldiering on, getting them to spread out and not letting them hang around when they get done. That hurts, because we know that we making cross country less fun. We just hope that these measures keeping them apart will also keep them safe, and maybe let them compete in a few races. 

Those races will be different. Much smaller than the races with which our athletes are familiar. We are trying to schedule some dual meets, because with teams as big as ours, two teams can fill up or exceed the maximum allowed in a meet. Some meets may use staggered starts spread out competitors. Others will just drastically limit entries and spread out the starting lines and lengthen and widen starting straightaway in order to let the field stretch out before having to make crowded turns. Some places will do both. No one will hang out at the starting line until just before the start. The athletes will wear masks until just before the race starts, and have to put masks back on as soon as they finish. The changes represent a way to cut down on the risk. And if we get in a few races safely it will be a lot better for the kids than no races or or having a couple of normal races and then a sharp stop to the season because of spreading infections.

This brings me back to this morning. It was hot for at 8:00 am start, but not nearly as hot as it would get today. Two groups of girls starting on different sides of a large field, running intervals around it. Forty-five minutes later two more groups arrive and start their workout while the first groups head off (in different directions in groups of 3-4) to cool down. The same thing happened for the boys, but on the track. Put simply, it's not nearly as much fun as it would be under normal circumstances. But we are making all of these changes for a reason. And that reason hit me in the face this morning when some girls smiled at each other and said "One more 'til one more." That little bit of normal, of working hard and sharing that hard work with teammates is important. It is a piece of normal that will, I hope, give kids a mental lift and make it a little bit easier to navigate our current reality.

[Side Note: Please don't take this as a "We need to find a way to let the kids have a season polemic." If anything this is a "Why are you not willing to make any of the sacrifices or changes that would let the kids have a season polemic."]

We apparently have not learned much

I am once again hearing people say "Kids need to be in school and they need extracurricular activities for their health." I agree. I am a teacher and a cross-country, track and field and robotics coach. I already experienced losing a season (track) and having a season cut short (robotics). The problem is that people are using this statement to argue that we need to send kids back to school face to face now. It is actually pretty much exactly the same situation as the arguments this spring that we shouldn't have restrictions and lock downs because the economic damage will be worse than the damage from the virus. A framing that completely ignored the reality that uncontrolled infections were inevitably going to lead to economic downturn, and that we are not going to get out of the economic downturn without getting the virus under control. While New Zealand celebrates 100 days without a case we are really not in any better shape than we were in April and May.

I am tired of people equating "lower risk" and "no risk." They are not the same. It is a fundamental problem with human's ability to really assess risk and the consequences of their actions. A recent study showed that nearly 100000 kids got infected by SARS-COV-2 in the last half of July. This was with schools closed. In Georgia schools open and shut back down or immediately have hundreds of students have to go into quarantine because of close contact with infected peers and teachers. These are very real risks when you open with too much community spread, and our nation has made itself the poster child for sending containment efforts off the rails. So it just not a fair comparison to try to frame this as deal with the virus or open schools. Making the same false choice front and center with the regard to opening the economy lead us to where we are now.

We are also back to arguing that there is a conspiracy to inflate COVID-19 infections. What is really infuriating is the number of people who argue that the testing protocols are inflating the number of infections are also arguing, often in the same argument, that the virus has actually been circulating since last fall and their were millions of infections not counted then. "The number of infections is vastly over-counted and the virus is not really that dangerous because there were millions of uncounted cases last fall and winter." How do you even argue against that reasoning? 

 Even worse, I am now seeing people citing articles like this one predicting future deaths (up 300,000 by the end of the year) and saying "See, there is nothing we can do, we should just give up." Then instead of swearing and saying unkind things I have to try to patiently explain the fact that the predicted death toll assumes that we continue the mask wearing and distancing we are currently doing. If we throw up our hands and send everyone back to school and work, it will only be for a few weeks and everything will shut back down AND the death toll will go well north of 300,000.

So here is the thing, whatever you think about testing numbers, more than 163,000 people have died from COVID-19. And before you start with the "Those numbers are being over-counted too" please stop and ask yourself about the logic. There is significant evidence that the death count is a significant under-count. This post from CDC addresses some of the issues people are citing without understanding. Simply put, we are experiencing a lot more deaths than normal. In fact even more than official COVID-19 death toll can explain. This is not just happening the U.S. and except possibly for Florida and Georgia here, it does not seem to be from official efforts to hide COVID-19 data. It's just an artifact of the situation we are in, and something that happens in a pandemic. Here is the takeaway to consider when you get tempted to argue that COVID-19 deaths are being vastly over-estimated. That means that something else is causing all those extra deaths, and by pattern it is an infectious disease. So it would mean we have an unknown infectious disease for which we have no test that has killed over a hundred thousand Americans so far. 

Even if you think the infection count is an over-count, look at the trend. Right it looks like maybe, just maybe, we have flattened the spike from the Florida-Texas-California-Arizona debacle this summer. But remember when you look at the graph that there is a 3-5 week lag between infections and deaths, so we are not out of the woods yet.

Now let's look at Georgia where the Governor felt that school opening went well except for the viral photos. You know, the school from the link above that had to shut down because of the new COVID-19 cases and the lack of a plan of what to do because of them. Yeah, definitely the problem was the photos. 

Now note the 3-5 week time lag and think about the fact that Georgia is just starting to see the start of the increase in deaths from all of those new infections. And opening up schools with all those crowded hallways is not going to make the infection numbers go down. 

Which brings us to my home state Ohio, the one where I am a teacher and coach. Our peaks are a lot lower (it turns out having a competent governor matters, who knew?) than Georgia's, but we have to think about the trends.

We maybe, maybe have flattened out the increase. We seem to have reached the latest peak on on hospitalizations and deaths. And thankfully across the country the numbers of deaths are not as high, because we have learned a lot about how to treat this disease so we can do the right things earlier and improve outcomes. But we are far, far from out of the woods. And still way too many people say "We need to go back now" and "#saveourseason" without being willing to do the things, like wearing masks, distancing and not going to parties, that would actually keep this under control. 

I am a teacher and a coach. I really want to be able to teach my students face to face, safely. Safe for them, for me, for their families and my family. I already experienced a robotics season cut short and a track and field season completely lost this spring. I have seen the angst of my athletes and dealt with my own disappointment. I certainly am not relishing the thought of a lost cross country season. We had seniors who were poised to battle for positions near or atop the podium in Jesse Owens Stadium, and I feel awful that they were denied that experience. Over 200 other athletes I coach were denied their seasons. My son was denied his season, and is starting his senior year under a giant cloud of uncertainty. But they were not denied their seasons by a evil governor, evil health director or evil school officials. They were denied their seasons by a virus that will not stop ravaging our country, our economy and our lives until we get it under control. Forcing us to have in person school and sports seasons this fall has a strong likelihood of giving us a few weeks or a month of school and games, followed by another shutdown. And certainly no chance for winter sports. Each time we do this it cuts deeper. And yet we seem determined, as a nation, not to learn. Not from the lessons of other countries that avoided it, like New Zealand. Or Italy, which was ravaged but got it under control. Or from our neighboring states, like New York, that was devastated and got things under control. Instead we are like the toddlers who want to keep sticking our hand back in the electrical socket as soon as it stops tingling.

Now for a rant. And this is not directed at everyone arguing for us to go back to school and have sports seasons. This is directed at the very vocal group who thinks there is no real problem, teachers are lazy and evil politicians are trying to ruin their lives by not letting their kids be in class and play football. [Let's face facts, when people say kids need extracurricular activities more than half the time they mean football. I know a couple people who have said they will sue if golf and tennis get to have seasons and football doesn't.] At the very least, if you are dead set (pun intended) on schools opening and sports happening at the very least can you stop accusing me and people like me of enjoying this pandemic. It's kind of old. My job is much less enjoyable because of the pandemic, and remote teaching sucks. I have already missed a sports season entirely and am facing the prospect of losing another. My son lost his junior year of track and is looking at losing his senior year of cross country on top of doing a semester of remote learning. I do not enjoy this. Not at all. I am tired of being told I don't care by people unwilling to actually do anything to get the virus under control.

Assessing Risk and Restarting School

OK, as the nation wrestles with when and how to open schools back up, I feel it is again time to make one of my lengthy posts on this crisis. I had kind of hoped by now we would be on our way to controlling the virus and getting things back to new normal, but I really should have known better. As I think about it, I am probably going to meander in this post, as I have a couple of points to make before sliding back to the question of addressing the opening of schools.

(Side note: If you want to get into a debate on whether this crisis is actually real or whether most of the scientists are lying please do it on another of my posts. I have to discuss that somewhat because it is integral to discussing risk assessment, but it's not the point of this post. And I am freaking tired of having that argument come up no matter what the post is about.)

Human beings are, in general, amazingly bad at analyzing risk rationally. There are a lot of reasons for this and a lot of different biases that come into play. (I have included a couple of links below.) Right now, it means that across the political spectrum and across the spectrum of the seriousness with which we take COVID-19 (sadly our president's actions have largely dictated that these two spectra are close to the same) this leads to issues. But the idea that people "on both sides" are assessing risk inaccurately has lead to a narrative that people on both sides are making equally rational decisions. That is the idea I want to take apart in this post.

I am going to start with the critique of what I view as people broadly "on my side" of the argument, to the extant that there are two sides. On the average, humans tend to be overly optimistic about risk. But once we tip over into pessimism/fear we tend to be overly pessimistic and fearful. This leads us to overestimate risk. Witness the woman this morning who freaked out when, as I approached her on the bike path and moved about seven or eight feet off the path, maybe ten feet or so from her, started yelling at me that I was poisoning the environment by not wearing a mask. When I run I don't wear a mask because it becomes a sweaty, wet mess really quickly. I do carry it so that if I have to stop near someone to cross a street I can slip it on quickly. All of the available evidence suggests that even two people without masks passing closely by each other outside are at very little risk. At the ten feet we were apart her screaming at me (with her face pointed toward me) probably put me at more risk than my running by her put her. And neither of us was in much danger from C-19. I also know people who have said they won't even have a conversation outside sitting 8 or 10 feet apart with our without masks. Unless these people have seriously health risks, they are over estimating their risk. The evidence is pretty clear that outdoor activities that don't involve a significant amount of time in close contact are pretty low risk. On the other hand, people in this category are making, in my view, a more rational decision than many people on the other side. They are prioritizing avoiding potentially catastrophic consequences. Do I think that if some of them had a better grasp of the actual risk they might change behavior somewhat? Absolutely. But it is not, at heart, irrational.

On the other side are all the people who started out in the "this is a hoax" or "this is no worse than the flu" camp. These are the people who were loudly crying "the cure is worse than the disease" in March. They are people who, to put it simply, do not understand infection models in a pandemic and relied on the expertise of people who largely do not understand infection models in a pandemic and/or experts who didn't really understand all of the data before making their initial predictions and have ever since been trying to slowly hedge their way out of that initial mistake without having to say "I was wrong" or even "I made my best estimate based on the data at hand but now we have more data." People in this camp underestimate risk in two fundamental areas.

First, they think that low percentages are the same thing as almost no danger. People tend to think of danger in terms of "will this happen to me" or to any one person. When they conclude very likely no, they then think there is no danger. This lets them dismiss COVID-19 as nothing worse than the flu when in fact it is far worse than any flue in at least the last 50 years and more likely the last 100 years. Over 150,000 Americans have died from COVID-19 (actually it is VERY likely this is a fairly significant undercount by 10% or more). People in this group seem to think that knowing some math and basic statistics lets them analyze information and find "the data" that proves their position. Also in this category is focusing only on deaths and not on the much larger number of long term health problems associated with C-19.

The second underestimation is that they adhere to their optimism in the face of evidence that suggests it is unwarranted. So they consistently say things like "studies show kids can't pass the virus" when that is simply not a reasonable position to hold any more. Or they say "death rates are declining" for weeks, trying to argue that because the ration of deaths to confirmed cases the virus is killing fewer people. When in fact it was starting to kill more people (and the rate of increase was increasing) and the ratio was only declining because the number of cases was skyrocketing. This position is, at its heart, irrational. Which makes it much harder to combat.

Some people who think low danger means no danger will stop and think if you can talk about the implications of their own numbers. I had a parent I know (I have taught a coached a couple of her kids) who told me she didn't think that more than a third of Dublin teachers would get infected if we went back to in person schools. And no more than half of the kids. And then she told me her (optimistic side) beliefs about death and hospitalization percentages. She told me "You know the chance that I die from this is very small. When I asked her if she was OK with 2-4 teachers dying and 30-60 being hospitalized she said of course not. She had never stopped to think about the implications of her own numbers.

The people in the second category are much harder to convince. So far the only thing I have seen change many minds is when they know someone who dies or when they or someone close to them gets seriously ill. Which is odd in and of itself because that really doesn't change the overall risk.

So this brings us to school opening back up and whether it should be in person. There is a small but very vocal group in the I will deny all the evidence and argue that there is no danger, or that the danger to kids psyches is greater, or that the danger to the economy is greater, or that teachers are just lazy or even that we are not going to be able to eradicate COVID-19 so we should just go ahead and let everyone get infected now. Anything they can think of to argue that schools should be open. Teachers, at least those who believe it is too dangerous to go to face to face instruction now, are really focused on this group and I think it is largely fruitless. We shouldn't ignore them, as their disinformation needs to be countered, but we are not going to convince them of any other position. It is people in the group who are conflating low danger with no danger that can be won over. When they stop seeing a low chance for their kid or their kids' teacher to be harmed as the same as no one will be harmed they may change their minds.



Links:

Humans and risk, covid specific: https://www.nytimes.com/2020/06/30/smarter-living/why-youre-probably-not-so-great-at-risk-assessment.html

Humans and risk, general: https://www.psychologytoday.com/us/blog/the-inertia-trap/201303/why-are-people-bad-evaluating-risks

Substantial Undercount likely: https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2767980

Kids 10-19 do spread the virus like adults: https://wwwnc.cdc.gov/eid/article/26/10/20-1315_article

Remember when people were saying cases were going up but not deaths, so it's OK?

Yeah, back then it was "deaths are going down" vs. "there is a big time lag, just wait." So now we are starting to get through the 3-5 lag between infections being reported and deaths being reported. Here is what the big three (Arizona, Texas and Florida) look like as of a couple days ago:

So now it seems pretty clear that we are not out of the woods yet in terms of deaths. If we let cases increase dramatically we will also see increases in deaths. The only thing that has "gone right" in the past couple of months is that we know more about treatment. That is a definite plus in that it means fewer people with serious complications and fewer dying. But still way too many dying when we could have beaten this a few months ago and had it largely under control. Now it seems like the only way we will ever make this manageable is rapid testing. Even if we get great vaccines 50% of Americans say they won't take one, and the data on immunity seems to indicate it last for at best a bunch of months. So our only hope is to leverage some people getting the vaccine with testing and contact tracing. We will also have the problem of people not being willing to quarantine, but maybe by combining all of these measures we can eventually get a handle on this.

STRS and Private Prisons

This post is not about COVID-19. But the COVID-19 era has also become the (maybe) Black Lives (really do) Matter era. STRS, the Ohio teacher's retirement system, has fairly significant investments in two companies that operate for-profit prisons, GEOGroup and CoreCivic. For many educators, myself included, this is real moral problem. Our deferred compensation is supporting the school to prison pipeline. The school to prison pipeline is one of the key drivers of the inequity that BIPOC (and poor white) our students face. We want our support for that system stopped, just as the California teacher retirement system decided to do. 

I will write more later about the huge moral and actual operational problems involved with private prisons soon. That conditions are bad (for both inmates and staff), that it incentivizes the unequal sentencing that is the reason for its existence and that private prisons are terrible at rehabilitation. Which makes sense because they have a vested interest high recidivism rates. And we can talk about the whole problem of kids in cages. Right now I want to focus on the idea that they are probably not that great an investment. 

Private prisons were supposed to make things better by being cheaper than publicly operated prisons and increasing the quality of services by inducing competition. In the 1990s, when we were building prisons like mad, this seemed to some like a good idea. For the most part, neither of these "good" outcomes has has happened. The research is somewhat mixed but it is fairly clear that there are at least not any big savings. On the other hand, there is considerable pressure to stop using private prisons. While the Trump administration reversed an Obama administration decision to phase out the use of private prisons at the federal level, it seems likely that Joe Biden will be elected president in November and re-implement the policy. A Biden presidency would also likely see big changes in our use of private prison operators for detentions at our borders. In fact, just the Democratic control of the House of Representatives does this. Furthermore, there is growing support for decriminalizing marijuana and already a lot of moves being made to move to treatment over incarceration for opioid and other addictions. All of these factors could very quickly make the stock prices of private prison operators tumble, and tumble rapidly. The rosiest up side predictions are that they might produce modest growth if we don't see a change in administrations. The stock values simply do not provide anywhere near the level of potential returns to justify this level of risk. And certainly not enough to justify the moral issues with teachers using their deferred compensation to support the school to prison pipeline and children in cages at our borders.

To sign the petition to call on STRS to divest from private prisons, please go to: https://alleyesonstrsohio.com/

Meaningfully discussion what is safe or not safe requires correct information

Let me start by saying this by saying I am not an expert in epidemic modeling. I do have expertise in statistics, I do have graduate classwork and some professional experience with epidemic data analysis and modeling. And in spite of that I am NOT an expert. Which is why when I want to know what is most likely to happen next, I read and listen to the words of experts. What I can do is explain how a lot of the reasonable sounding, statistical sounding arguments floating around out there are either wrong, make unjustified assertions, or both. To illustrate I will use some words used to argue for five days per week in person school for everyone who wants it in the school district where I teach. My district is the Dublin City Schools, in Franklin County, Ohio. 

We are not in level 4, we are in level 3 and they removed the star last week that warned we might go up to 4. Franklin County is increasing in cases, but has had a downward trend in deaths for 8 weeks, and hospitalizations for 7 weeks. 

OK, let's address the "big claim" here, that cases are up but deaths are down. Here are the graphs of the seven day rolling averages for cases and deaths. 

So on it's face this looks kind of like a true claim. It is true that we have learned a lot about treating this disease so it has become somewhat less deadly. The problem is the same one we are having right now with people arguing that the death rate is dropping dramatically nationwide. When they say "death rate" they mean case fatality rate. And the reason the case fatality rate is dropping dramatically right now is not that fewer people are dying but that the number of cases is rising quickly. On the other average deaths are taking almost 2-4 weeks to occur after positive tests, with another week or more until the deaths are actually reported as COVID-19 deaths. So there is a 3-5 lag between the case numbers and the death numbers. If we put a line in the cases graph we get:

Noting that the death numbers are small compared to the case numbers so the graph won't be a smooth, look again at the deaths graph above, compare that the part of the cases graph to the left of the line, then think about it a bit and tell me what seems likely to happen to deaths over the next month? 

If you look at the percentage increase in how many more tests they have done, the pattern of increase in cases follows the testing increase almost exactly. We don't have more cases, they are just testing more and detecting the asymptomatic cases that have always been there.

OK, first off we don't know the test positivity rate, so this just can't justify this claim. We do have an estimated R-nought value of 1.11 for Franklin County, meaning the problem is growing not shrinking. Overall in Ohio the test positivity rate has gone from 4.3% to 6.3% in the past month, which argues very strongly that this is not a case of just having increased testing rooting out asymptomatic cases that have been there all along. And the increases in all of Ohio outstrip the increases in testing. In fact about 1/3 of all the cases in Ohio have been identified in the past three weeks but nowhere near 1/3 of all the testing occurred in the corresponding time frame. 

Also, the Dublin area has had very low numbers all along, with only a few hundred cases total. Only about 0.4% of the population in Dublin has even had this. 

The number of cases is growing in Dublin, just like in the rest of Franklin County. This is an attempt to throw in numbers that sound like they might support the "this is not a serious problem" idea but they don't. Also, a large part of the Dublin City Schools is in the City of Columbus. So you really need to look at the number of cases in all the parts of DCS. Like Dublin, the cases in Columbus are going up rapidly.

The common flu also is transmitted asymptomatically, and is much more dangerous to children than coronavirus, yet we don't test everyone for the flu each year. 

and

Yes, vulnerable populations need to be protected, but shutting down businesses and schools and destroying our country is not the answer to this virus. I am glad the schools are giving an option for people who are vulnerable or are scared, but I really hope those of us that aren't are given an option for our kids to return to school full time.

The flu is not much more dangerous to kids than COVID-19, we do a ton of flu testing every year, we aren't testing anywhere near everyone for SAR-COV-2 (that's part of the problem), and kids are not the only people we are worried about. We are also worried about kids spreading the virus. We don't yet know whether COVID-19 is more deadly than common influenza's than kids. We are nowhere near being able to argue that. When we closed schools we isolated kids from infection. It does appear that younger kids (under 10) are much less likely to contract it than older kids and adults. So it might turn out to be less deadly. But so far so many fewer kids have contracted it that we just don't know. We do know that there are other serious health risks with COVID-19 that are far more common than in influenza. So the evidence right not points to COVID-19 not being less dangerous for kids than influenza, and certainly does not support a claim that is less dangerous. W

e do lots and lots of flu tests every year. including this year. We also have flu vaccines which allow us to mitigate risk and spread. Initial flu tests take tens of minutes, so they are done right in a doctor's office. If we had similar testing for COVID-19 we might have controlled it. 

Finally, the biggest worry is that kids will spread COVID-19 to school staff and to the their families and neighbors. Even if we knew no kid would get seriously ill, if we went back and did school as normal we would have a lot of teachers, bus drivers, custodians and cafeteria workers die in Dublin. Because almost all of the adults would get it. We would also have a really high percentage of the parents of our students get COVID-19, and some of the them would die. And even more of the adults would suffer long term health impairment. 

Some Links Used:

https://github.com/nytimes/covid-19-data

https://www.wsj.com/articles/how-deadly-is-covid-19-researchers-are-getting-closer-to-an-answer-11595323801?mod=e2fb

https://coronavirus.ohio.gov/wps/portal/gov/covid-19/dashboards/overview

https://covidactnow.org/us/oh/county/franklin_county/?s=748128

https://drive.google.com/file/d/1wNl36_DQAowjZ6MzvkhjZsMphOny3mYr/view

https://www.cincinnati.com/story/news/2020/07/13/about-one-third-covid-19-cases-ohio-past-three-weeks/5429686002/

Can masks really help?

One of the big problems in looking at math in a situation like the pandemic, is that people, even people who are generally good at math, tend to be really bad at getting an intuitive feel for probability. Particularly in cases where there are a lot of probabilistic outcomes to factor in. To help my students understand this, I created a simple simulation to model contagion spread. It is based on the ZooSimulation that I do in my AP Computer Science and IB Computer Science classes every year. Basically you create autonomous agents that are placed in a simulated environment and interact. 

For my contagion simulation I ran simulations of 300 people moving about an environment randomly. For a baseline, I ran the simulation assuming everyone moves at every step of the simulation and that if an infectious person (infected are red) gets next to someone who is not infected and not immune (these people are blue) they will infect that person. In this stage of the simulation I also gave each infected person a 5% chance of "getting over" the infection at each step in the simulation. If they get over the infection they turn purple. These people cannot infect anyone else and are immune forever in the simulation. (Yes, I know that we now realize that immunity likely only last for a period of months, but this simulation was created to demonstrate how the math works. I will probably update it so that after some number of steps the purple people can turn blue again.) Here is a typical run for the baseline:

So the next thing I simulated was to add in social distancing. To do this, I simply made the people move less frequently. That would reduce their interactions with others. For this round, I made everyone in the simulation have the same chance of moving at each stage of the simulation. This was for simplicities sake. One of the more advanced versions a few of my students worked on this spring allows for a range of movement likelihoods in order to figure what percentage of population needs to socially distance in order to really inhibit spread. It does turn out that the average chance of moving is what really matters. So in this next run I had everyone move only 1/3 of the time.

You can see that this does tend to inhibit spread. But we decided that this was too optimistic to be realistic. So for the run after that we used everyone moves 2/3 of the time. 

This still was a lot better than everyone moving all of the time. Next we considered masks. For this first run we had masks be 25% effective at preventing infection. Note that this does not necessarily mean that everyone is wearing 25% effective masks. If a mask reduces the chance to you give an infection to someone by 40% and the chance you get an infection by 10% (both of those are lower that current estimates for cloth masks) and everyone is wearing masks then there is only a 54% chance of the infection passing from the infected to the non infected person. (0.6 x 0.9) In other words, that makes the masks 46% effective if everyone is wearing masks. 

The situation is a little more complicated if not everyone wears a mask. Using the above masks (and remember those are considerable less effective than current estimates), with 2/3 of the population wearing masks, you get  (4/9)*.54 + (1/9)*1 + (2/9)*.6 + (2/9)*.9 = 0.6844 or masks being net 32% effective in stopping infections. A little more on this math later. Now here is a simulation run with masks being 25% effective and people moving 2/3 normal. So not super effective masking or distancing, but something. 

Now we the infection spreading much more slowly. This is important not just for bending the curve purposes, but also because it makes contact tracing and isolation much easier to do and much more effective. I have some later models that estimate how likely it is a person gets tested and assumes that 90% of those who test positive will isolate themselves. If you can slow down spread this allows you to prevent outbreaks from ever growing out of control.

So let's think about mask effectiveness for a little bit. The masks above were only 40% effective in reducing the chance you infect someone else and 10% effective in preventing you from getting infected. If everyone wore them we could cut the infection chance by 46%. If only 2/3 of people wore the masks we could cut infection rates by almost 1/3 (32%). Here is a run with 50% social distancing and 33% effective masks.

That is starting to look like something actually controllable. Actual cloth mask effectiveness is difficult to measure, because so many factors like regular washing, wearing it correctly, tightness of fit and other things intrude. Meta-analysis is heading toward about a 70% reduction in the chance you spread the virus on the average and about a 20% chance to protect you from getting infected. If everyone worse masks that would mean masks would stop 75% of infections. 

There is more research showing the effect of masks all the time now. I have read three new articles in the past week. Think of a mask this way, effectively it amplifies the distance between you and someone else and decreases the time you are near each other. A mask traps some particles, and reduces the velocity of others. So infected droplets spread out more slowly over less distance. Effectively doing the same thing that spending less time in contact and being further apart do.

Masks are not magic. Only complete isolation can guarantee you won't get infected. And that isn't practical. But masks coupled with distancing efforts could actually make this pandemic something that we could navigate much more safely. We would be able to shut down just areas where infections were spiking, and shut down for far less time. We would be able to contact trace because the speed of infections would slow so that for a lot of places there would be no need to go on full lockdowns.