Risk calculator tracks odds of infection

Center for Social Research director created a tool that illustrates the need for the stay-home order.
Risk Calculator
Exposure to even a small group of people increases the risk of contracting the disease exponentially, according to risk calculations. Courtesy iStock

Maybe despite Gov. Gretchen Whitmer’s “Stay Home, Stay Safe” order, you’re still longing to go out. A tool created to illustrate the risk of gathering together shows why that’s a bad idea.

Before the March 23 order to shelter in place came down, Neil Carlson, a data expert who is director of Calvin University’s Center for Social Research (CSR), was interested in answering the question, “Am I really that at risk?” of contracting the virus by attending a group gathering.

During the weekend of March 21-22, Carlson created a visual meeting risk calculator as part of an interactive dashboard that tracks the spread of the COVID-19 pandemic and informs people about known risks.

The calculator projects how risky a person’s social behavior can be based on the estimated infection rate in the region the person lives and works in.

Now that everyone is effectively banned from leaving their homes unless they are getting groceries or doing other necessary tasks, or they’re a critical infrastructure worker, the tool isn’t needed as the basis for decision-making on whether to attend meetings, but Carlson said those interested in understanding the reason behind the executive order to stay at home might still find it useful.

“I hope this is helpful for creating some context for why public health officials and statisticians are alarmed when the general public is dismissive of the risks of exponential growth,” Carlson said.

The risk calculator — which draws from the public work of the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University and was inspired by a widely read blog post by Tomas Pueyo of Course Hero as published on Medium — is available at the CSR’s Tableau Public page, at tabsoft.co/2RgeGwD.

The simulator uses seven data points to calculate the probability of at least one infection being present in a group of various sizes: deaths reported to date in one’s county, estimated fatality rate, estimated cases active at infection, estimated cases active now, estimated infection rate, estimated healthy rate, and meeting size.

Based on the one death that had been recorded in Kent County as of March 31, and the approximately 115 presumptive positive cases, the calculator estimated that the risk of at least one infected person being in the room during a group gathering of 100 people — if no social distancing controls were in place and people weren’t handwashing, Carlson said — would be about 11.5%.

“Later, if there are five deaths in the county, that same meeting of 100 people has a 45% chance — nearly ‘a flip of the coin’ — of someone infectious being in that room,” he said.

As noted by Spectrum Health CEO Tina Freese Decker in a March 30 address to the community, it is known that COVID-19 is “far more dangerous” than the flu in many respects, one of them being that after two months, one person with COVID-19 will pass it on to up to 99,000 people, so even an 11.5% risk of being in the room with an infected person is far too high.

Assuming the worst using models based on state, national and global data, Freese Decker said the rate of growth of infections in Michigan is at least as fast as New York’s, if not faster.

“The modeling for our area shows that at its current rate, we would exceed demand for hospital and intensive care services in early May, and this would last for many weeks. This peak in cases would be more than our health care system or any health care system could handle,” she said.

This is why it is so essential that people stay home, flatten the curve, and that hospitals free up beds for the coming surge, Freese Decker added.

Carlson said in addition to the risk calculator, the CSR site features digital visualization tools that allow users to see how the spread of the COVID-19 pandemic is happening on a country-by-country and state-by-state level.

CSR is taking suggestions for other models that would be helpful to develop, as well. Someone can suggest a model by emailing csr@calvin.edu or sending a message to the Calvin University Center for Social Research Facebook page.

“For your readers and for businesses, I’m interested in thoughtful requests for feature enhancements (and) questions about the applications of the things. To the extent that there’s someone who’s like, ‘I really do want to use this, but I want to make sure I use it right,’ have them get into touch with us and we’ll try to help,” Carlson said.

CSR is researching data needed for comparisons of COVID-19 to past epidemics and will soon include per capita rates of COVID-19 infection for the U.S.

Referrals to new public data sources are welcome, Carlson said.

Founded in 1970, Calvin University’s Center for Social Research (CSR) is a learning partner for social research and development.

The center conducts social-scientific research projects, taking data from collection to reporting through focus groups, statistical analyses, program evaluations, maps, interactive data visualizations, surveys and more.

CSR conducts and collaborates on several large research projects and several dozen smaller projects annually for academic, public sector, nonprofit, religious and business organizations.

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