To start, let me explain a bit about the role of modeling in my decision making, since the outbreak of COVID-19. I’ve taken into consideration a variety of models from researchers all across the world. There are often widely different projections from those about the state of Illinois. Some of this disparity is the result of methodological differences, but much of it also is due to data access and quality. The earliest coronavirus models that we had in the United States had to rely upon data from other countries applied to our national landscape, and certainly there was a real benefit in those very early days of getting educated estimates of what the virus’s effect on Illinois would look like regardless of where that early data came from. But the picture that gets painted by modeling gets better when it’s based off of what’s actually happening on the ground in Illinois data that can only be gathered with the passage of time.
We now have what we didn’t have two months ago, an understanding of what COVID-19 cases, deaths hospitalizations ventilator and ICU usage look like every day in Illinois. Even so, two months is not a lot of time in the world of modeling.
That’s important because the very essence of a model is that it gets smarter over time. How well you consistently test past predictions against current reality and then adjust projections accordingly. Or to put it simply, the more facts that you have, like exactly how many people went into the hospital with COVID-19 on a certain date, the better your ability to predict outcomes on any later date.
Notice I say it becomes better, because it never is exact. There is no crystal ball available to us. There are only estimates. Illinois is the proud home to some of the finest researchers and research institutions in the world, and still it is always the case that different modeling teams come to different conclusions.
So I undertook a project to give me the best possible approximations of future COVID-19 illnesses in Illinois, that would then allow me to make decisions about what resources we would need to keep Illinoisans alive, and recovering. And what urgency would be required in decisions about whether to initiate new mitigation strategies or extend existing ones, like the stay at home order. I have known from the start that even the best projections are going to have a great deal of variance. But knowing the boundaries of that variance informs my decision making. So we convened top researchers from the University of Illinois Urbana Champaign, the Chicago and Illinois Department of Public Health Northwestern School of Medicine. The University of Chicago. And we also brought in outside consulting groups. They worked as a cohort, under civis analytics, using the most comprehensive data available for the entire state of Illinois. Suffice to say the findings we’re discussing today about the state of Illinois were put together by some of the best scientists doctors researchers from some of those great institutions that I just mentioned.
I want to look first at the projected fatalities. As you can see from the graphs that are next to me, Illinois is now looking at a peak, or plateau of deaths per day. Somewhere between late April and early May.
Why a range instead of an exact date? Well, everyone wants to look at the median line as a guide, that nice clear line that cuts through the big shaded section on all the models circulating online.
But reality is not quite so simple. Look at the actual deaths from the past few weeks on the graph next to me and look at the median projections going forward. Reality swings up and down, sometimes drastically affect that can’t be captured with a simple median line. What we have to consider is the whole shaded area that shaded area shows the range that researchers are 95% confident that things will land. That’s a shaded area you would see in differing shapes on every model.
To be clear, the fact that the variance is large doesn’t make a model less useful, but it does, nevertheless, make it clear that it is only a tool to be used.
I worry that people think the model is some miraculously accurate view into the future that is going to tell us exactly what we need to do and when it’s not. It won’t. I guarantee that the model that we’re sharing today will change in the coming days as projected numbers about those days are replaced with actual numbers.
A model is an imperfect tool that we use to add context to the actual numbers that we can chart every day. Cases, fatalities ,hospitalizations, positive test results, ventilator and ICU usage.
I also want to explain a bit about this change in our estimated peak cases. The concept of flattening the curve, only just entered our common vocabulary in the last few months, and it’s really crucial to understand our approach.
Weeks ago, many models, both those produced by our in state experts and those from around the nation, predicted an early or mid April peak for Illinois. But as the weeks have progressed those models have come to look quite different. That’s not because those models were bad models. Instead it’s because their inputs got better as time went on, real time data came in, and importantly Illinoisans protected each other by staying home.
Human behavior is exceptionally difficult to measure and even harder to predict. So that last part about staying home has made all the difference in our progress. Also, and this is very important, the most sensible and responsible use of a model in a public health crisis, like this one, is to pay close attention to the worst case scenario. In other words, when building hospital beds, purchasing and acquiring PPE and ventilators and making decisions about mitigation efforts, public officials should assume that the worst end of the model range could happen, and take that into account in planning.
…Pushing out that peak is a natural consequence and the best indicator that we are flattening the curve. That’s what you’re aiming to do, slow down the rate of transmission, which leads to a slower rate of increase over a longer period of time. Hence, a later, and lower peak, pushing the peak further down the line might not sound like good news but I promise you, it saves lives.
And make no mistake, Illinois has saved lives by staying home and social distancing we have kept our infection and death rates for the month of March and April, thousands below the rates projected.
Had we not implemented those mitigation strategies, the good people of this state have allowed our healthcare professionals, the ability to treat patients to the best of their ability without having to make dark choices, very real choices that doctors in other countries face about who lives and who dies. That is a historic and heroic act carried out by all of you.
Your efforts to protect your families, protect your communities, protect each other, have also given us another tool. And that’s time, time to build up our hospital capacity in terms of beds ventilators and healthcare workers, time to prepare for the kind of surge, that could occur. Anytime as a result of a virus from which no one is immune and capacity, we built in August of 2019. Back in a world that had never heard of COVID-19, Illinois had an average of about 26,000 total hospital beds available.
As of today, our total bed count in existing hospitals is more than 31,000. Back in August we had about 2000 ventilators, that number is now more than 3200 ventilators, and we’re building our healthcare workforce too. There are now 5000 out of state and former medical professionals who have applied for temporary licenses to join Illinois fight against COVID-19. We’ve built up our hospital capacity significantly.
But if we let up now, we would have nowhere near the kind of hospital capacity that we would need the projections are clear. If we lifted the stay at home order tomorrow, we would see our deaths per day shoot into the thousands. By the end of May, and that would last well into the summer, our hospitals would be full and very sick people would have nowhere to go. People who otherwise might have won their fight against COVID would die because we wouldn’t be able to help them through.
No amount of political pressure would ever make me allow such a scenario for our state, our beloved state of Illinois.
Well, I already fell better now that we’ve got Illinois’ John Oliver on it.
Comment by Candy Dogood Thursday, Apr 23, 20 @ 2:59 pm
I appreciate the thoroughness that Pritzker is putting into explaining this and his willingness to acknowledge the inherent flaws in attempting to model this out. Science is not perfect particularly in the early stages of defining a problem. There are a lot of variables here. Some known, some unknown. The important thing is that we’re getting this information daily as sobering as it may be.
Comment by Pundent Thursday, Apr 23, 20 @ 2:59 pm
Prof. Nigel is EXACTLY as I pictured him and, his rocket analogy is excellent. I am more comfortable that he is on the team.
Comment by Proud Sucker Thursday, Apr 23, 20 @ 3:00 pm
The Governor has the hammer, and he’s not done treating everything like a nail.
Comment by Pat Quinn Mowing Grass Thursday, Apr 23, 20 @ 3:02 pm
Nigel! I’ve met him at parties. He’s really cool, in a very nerdy sort of way
Comment by Cheryl44 Thursday, Apr 23, 20 @ 3:03 pm
Rocket Science is not necessarily hard, but it is spectacular when it fails
Comment by bhartbanjo Thursday, Apr 23, 20 @ 3:13 pm
“I see your pain. And I am so, so very sorry for it. But for every person who wants to go to dinner or hang out with friends in a park or swing open their salon doors, there is a family mourning the death of someone they love.
There is a parent, a child, a friend who would give anything to have their greatest strain be the difficulties of staying home, and not the unimaginable pain of a life loss too soon.”
Kudos to the speechwriter. I wish this message resonated with the cahoots asking for a Georgia-like reopening.
Comment by Dee Lay Thursday, Apr 23, 20 @ 3:17 pm
20 times higher? Wow.
I think I’m in love with Nigel. Hope we see more of him.
Comment by Rachel Thursday, Apr 23, 20 @ 3:18 pm
Our calculation show…..wouldnt mind seeing these.
Comment by Blue Dog Dem Thursday, Apr 23, 20 @ 3:20 pm
Weekly appearances from Nigel please!
Comment by In 630 Thursday, Apr 23, 20 @ 3:20 pm
“Hold Until Relieved” — The Longest Day. And that is what we must do; hold onto our resolve to stay home, practice social distancing, limit our travel, and the other right things to not merely flatten the curve, but flatten Coronavirus 19 into the ground. We have our first victories in flattening the curve, and slowing the spread, now “let us go forward together with our united strength” (W. Churchill, 1940) and finish the job.
Comment by revvedup Thursday, Apr 23, 20 @ 3:21 pm
I very much appreciate the Governor’s communication style - he uses affirming language and recognizes sacrifice. It is refreshing to hear in an Illinois leader. I cannot imagine recent predecessors communicating these complex and difficult decisions nearly as well - nor can I imagine them making such decisions in a timely manner.
Comment by Morningstar Thursday, Apr 23, 20 @ 3:38 pm
Are the figures shown on the right of the podium available anywhere? I’d like to be able to read them, hard to see on camera. TIA.
Comment by White Power Ranger Thursday, Apr 23, 20 @ 3:40 pm
Can we get Professor Nigel Goldenfeld on a T-shirt?
Comment by Candy Dogood Thursday, Apr 23, 20 @ 3:56 pm
JB Today. You want modeling? You been asking about modeling? I got your modeling right here, buddy.
Comment by Southern Skeptic Thursday, Apr 23, 20 @ 4:10 pm
== I cannot imagine recent predecessors communicating ==
Good lord, could you imagine if Rod was still governor right now? That would have made the clown show daily White House briefings look like masterpiece theatre. Guy would be hiding in the bathroom while Bradley tried to coax him out with treats like a scared labradoodle.
Comment by Lester Holt’s Mustache Thursday, Apr 23, 20 @ 4:13 pm
The model 3T, has been replaced by a new model.
Comment by Blue Thursday, Apr 23, 20 @ 4:25 pm
=== like a scared labradoodle===
I saw what you did there.
Comment by Rich Miller Thursday, Apr 23, 20 @ 4:44 pm
Governor Pritzker’s explanation was a lot more rational and sensible than listening to Darren Bailey rant on the courthouse steps before filing his lawsuit.
Comment by SIUEalum Thursday, Apr 23, 20 @ 5:05 pm
==This is ridiculous and dangerous. You’re all a bunch of cowards. Face your fears, when you come out the other side, you’re stronger for it.==
As OW says, you can’t un-die. So, no, we may not come out on the other side and be stronger for it. There’s a lot of health care workers, and other front line essential workers that faced their fears and are now dead. There’s even a few pastors that held church ‘because’ and are now dead.
I’ve got elderly parents at an assisted living center and a spouse with some of the high risk pre- existing conditions that could be dead if I bring it home to them. Is that worth facing my fears?
Comment by thoughts matter Thursday, Apr 23, 20 @ 11:01 pm