COVID-19 Cases in Montgomery County

Last update: Thursday, May 14, 2020

Here are some statistics on COVID-19 cases and deaths in Montgomery County. This page will be updated every few days.

Feel free to post questions and suggestions about the charts below. Updating and publishing these charts take a lot of time, so please leave a comment or share this post if you appreciate it and would like me to keep updating on a regular basis.

Cases per Zip Code

First, here are the number of cases per zip code in Montgomery County. I’ve only posted the top 10 zip codes and a couple other ones. The first chart is plotted on a linear y-axis, and the second on a logarithmic axis. Number of cases are obtained from the Maryland Department of Health. For people interested in statistics compared to population, the chart labels show the number of cases per 100,000 people (population data from the US Census Bureau 2018 American Community Survey, obtained from Maryland-Demographics.com)

Below on the left is a chart showing the number of new cases per week (I chose to show a rolling 7-day average as opposed to daily numbers because of the high variability of the latter). On the right is a chart showing how many of these COVID-19 cases are nursing home residents, according to the state health department dashboard, “Maryland COVID-19 in Congregate Facility Settings“.

Demographic Correlations

Below are several charts showing the correlation between the number of cases in each zip code, normalized by population, and the following statistics:

• Population Density
• Median Age
• % of Population under 18
• % of Population over 65
• Household Income
• Homeownership (% Renters)
• Race (% White, Black, Asian, and Hispanic)

As you can see in the charts below, the strongest correlations are % Hispanic, % under 18, % White, and household income–NOT density or % over 65.

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Are we flattening the curve yet?

Below are charts showing the trajectory of COVID-19 cases and deaths in various Maryland counties.

Drawing the chart this way (new cases vs. cumulative cases) helps to show when states and counties are escaping the scary exponential stage of a highly contagious disease outbreak.

“Are we still on the rocket ship of contagion, like the US? Or have we managed to hit the emergency eject button, like China?”

Henry Reich (@minutephysics), “How To Tell If We’re Beating COVID-19”

For an easy-to-follow explanation on how to read this type of chart, and its advantages and shortcomings, I encourage you to watch this 7-minute video:

Charting the trajectory of an infectious disease outbreak:

1. Straight diagonal line = uncontrolled exponential growth
2. Bending away from diagonal = still more new cases each day, but at a decelerating, non-exponential rate
3. Sloped downwards = fewer new cases each day
4. Rapid drop = outbreak contained