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Aug 17, 2020

4 min read

COVID in Washington state, charts per county (Aug 14, 2020)

Here are charts for Washington State counties. These charts rely on the New York Times’ published data on COVID-19 in the United States. I am primarily use their county-level data set together with population estimates (Wikipedia reports on US Census data from 2019).

I have produced charts of new cases of COVID-19 as

  • 7-day trailing averages
  • scaled to cases per 100k.

All of my charts and tables are shared in a public Google sheets document:

Charts

As we remember, in March, Washington State was above average in new cases, but has now stayed below the US average for the next five months.

Against its own state, King County was above average for March and April. Not until May was it trending below the state average.

There is a small peak on July 6th of 6.79 case per 100k where King County hit the state-wide average. But, past that, King County has maintained a below-average trend to-date.

It is important to remember that King County’s population of 2.253 million accounts for 29.6% of the entire state. This is why its chart has less dramatic peaks and valleys.

Yakima has been the focus of concern, and when scaled state-wide, we can see a pattern of above-average cases that simmered in April and picked up dramatically after that. Its efforts to control the virus are showing progress. In last week of July and first week of August there was a considerable drop in new cases. While encouraging, Yakima still remains above the state average in cases per 100k.

Yakima has a population of around 251k which is almost ⅒ of King County. Seattle itself counts for 747k residents. By scaling Yakima’s case counts to counts per 100k, we see just how much higher a proportion of the population had become infected.

I have roughly tried to keep the vertical scales equal, 0 to 25 for King County and 0 to 65 for Yakima, and rendered so that you can overlay King County vs Yakima in your head.

These 5 counties show trends that are on the rise and above-average. I have included raw numbers alongside these graphs (and population numbers) which should help the reader contextualize the trendlines on the left.

Although these counties are still above-average now, they all recorded peak numbers that placed brought them high above average in July. August marks a promising improvement for each of these counties.

Notes

I chose these two transformations to help readers identify how COVID-19 is trending in each chart and to allow readers to make fairly direct comparisons county-to-county.

These charts compare each county against the entire state. This allows us to say whether or not a county has generally been doing better or worse than the rest of the state. I am using the trailing averages and trend line comparison to mitigate the way that testing patterns have changed since the early months.

I have refrained from speculation about the reasons for each county’s performance in this post and concentrated on simple language: above vs below average and a month to month comparison.