Thread by @AWhitTwit

I've been working to try to figure out the cause of this discrepancy, and I think I finally understand the situation (as well as any lay person could). Here's the lowdown - a story in 11 tweets. 1/

https://twitter.com/AWhitTwit/status/1308507510014238720?s=20

By way of review, I've been keeping track of the Monterey County COVID data since the county first started making data available on their website. I do this b/c I'm curious & b/c it's critical that I understand the data for making school board decisions co.monterey.ca.us/government/dep… 2/

Because the county does not show you the data over time (except for cases and tests), I've been keeping my own dashboard (of sorts). Even if/when the numbers are off, looking at trends is very useful. You can see it if you want. docs.google.com/spreadsheets/d… 3/

Week before last, I met w/ the Asst Director of Public Health at the Monterey County Health Department (via Zoom). She described how complicated it is to track testing & case data b/w various testing facilities, the county & the state. Bottom line: "The #'s will never match." /4

I am very sympathetic to how hard this is, but I wanted to see for myself where & how the numbers diverge. So I submitted a public records act request to the CA Dept. of Public Health for the county-level testing data (which is not available on the CA Open Data Portal). 🧐 /5

B/c I can't resist, here is a link to the PDF (!!!) I got from the state with Monterey County COVID cases & testing data (with & without prison data). 4 variables provided in ROWS across a 19-page PDF. GLORIOUS. One for the #datalibs, to be sure. /6
drive.google.com/file/d/1sXJ9Tx…

What it comes down to is that SARS-CoV-2 tests are being conducted all over the county & not all facilities provide all of their testing numbers to @MCHDPIO. Instead, they hand them up to the state-level system, UNLESS it's a COVID+ case. They tell the county about those. /7

What does that mean? It means that the county data are heavily skewed. They get most of the COVID+ case numbers, but aren't getting all of the testing numbers. It makes the county-reported positivity rate way off. How far off? VERY. Like 3.4% vs. 11.7% for state vs. county. /8

A positive spin on this is that we are doing much better in Monterey County than the Health Dept's COVID dashboard indicates. Our case rate is still too high, but we're doing a lot of testing (2-3X what the county reports). /9

My conclusion is that we should trust the weekly CA Blueprint for a Safer Economy data for snapshots of rates, & use local data for keeping track of trends (case rates, hospitalizations, deaths). covid19.ca.gov/safer-economy/… /10

I'm glad to better understand our COVID data, but am very frustrated that it took a records request to get the data I needed. It shouldn't be this way - all CA has to do is share county-level testing data. My sincere thanks to @MCHDPIO for their transparency & hard work. /end

So I can share on FB, @threadreaderapp please unroll. ✨