A Deeper Dive into Understanding Neighborhood Covid-19 Numbers by Molly Tolzmann

Ed. Note: Molly lives in Petworth. Molly is a hero for doing this. Huge thanks to Molly Tolzmann. Truly. You can explore the interactive map below.

State of the neighborhoods: This week’s big picture has not changed substantially. We see the same 5 neighborhoods as last week at each end of the spectrum, for most and fewest cases per 1,000 residents. A reminder that more data and maps are available here.

Notable this week: We got several days of neighborhood-level testing data from the city for the first time. Whether they will continue to report this (and whether they’re making other changes to the way they report testing) remains to be seen, but the few days they did give us make for an interesting snapshot in time.

Here’s a chart showing the per capita testing rates by neighborhood as of May 21, the last date for which testing data was provided. This chart shows both the cumulative number of tests per 1,000 neighborhood residents, as well as the rate of positives.

Generally speaking, neighborhoods that have seen higher rates of testing have also seen a higher proportion of positive cases: Neighborhoods below the median for test rates (meaning 53 or fewer tests per 1,000) had a May 21 median positive rate of 14.8% and 6.2 cases per 1,000. Neighborhoods with more than 53 tests per 1,000 had a median positive rate of 24.5% and 16.3 cases per 1,000.

Now that we have seen some testing data, it’s clearer that the differences in case rates between neighborhoods are not simply due to the quantity of testing. For example, the higher positives rate in Brightwood (22.2 per 1,000 on May 21) vs. Bloomingdale (7.1 per 1,000) isn’t simply because more people have been tested in Brightwood. More than twice the proportion of Brightwood tests have been positive compared to Bloomingdale’s. If we get more testing data over time, we can monitor how and how fast the rate of testing is changing in each neighborhood and how this relates to the number of cases.

The 10 neighborhoods that saw the biggest weekly increase in positive rate are more concentrated in DC’s north-central corridor than they were last week. For reference I also included the as-of May 21 testing data for the two pools in the chart below.

We still have a stark disparity in profiles between the pools of neighborhoods where the case rate is changing the most and least, if slightly less of a disparity than last week. As the conversations around reopening grow louder from all sides, I would bet that attitudes are shaped in part by what the pandemic has looked and felt like in each of our own immediate neighborhoods. The data continues to reveal that we have had very different experiences.