COVID-19 Analysis for March 31, 2020

1. Caveats and Comments
1. These are not confidential. You can freely share this output freely. The code is available at
https://github.com/StevenLShafer/COVID19/.
2. This is my analysis, not Stanford’s analysis. My understanding is that Stanford’s internal analysis, done to plan resource
allocation at Stanford, shows substantially longer doubling times. This is reassuring for those of us working at Stanford.
3. The data are from usafacts.org. Here is the file: https://usafactsstatic.blob.core.windows.net/public/data/covid-
19/covid_confirmed_usafacts.csv. The data are collected from state and county public health departments.
4. With trepidation, I have changed the fits. Previously I used two log linear fits. However, because the curves are starting to truly
flatten, I now fit the second curve to exp(log(observed Y on day 1 of final segment) + peak * (1-exp(-k * delta time))). This is an
empiric function of the rise to steady state.
5. The number printed on the graph is the projection for a week from today. Because that is only a week out, it is probably not far
off. However, the "peak" in the caption is the estimated total peak at time = infinity from the model. I have very little confidence
because it is a projection will into the future.
6. The idiosyncratic locations chosen for the analysis reflect where Pamela and I have friends and family. I’m happy to add other
regions. Also, I’m happy to add people to the blind CC distribution list. Just let me know.
7. Send any questions to steven.shafer@stanford.edu.
1

2. USA
399,606
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's USA Projection as of 2020-04-01
Initial doubling: 2.1 days, Predicted peak: 1,280,450
2

3. New York City
10,824
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's New York City Projection as of 2020-04-01
Initial doubling: 1.7 days, Predicted peak: 21,514
3

4. Santa Clara and San Mateo
1,833
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's Santa Clara and San Mateo Projection as of 2020-04-01
Initial doubling: 3.4 days, Predicted peak: 5,777
4

5. San Francisco
559
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's San Francisco Projection as of 2020-04-01
Initial doubling: 4.1 days, Predicted peak: 734
5

6. King County (Seattle)
3,454
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's King County (Seattle) Projection as of 2020-04-01
Initial doubling: 2.2 days, Predicted peak: 8,973
6

7. Multnomah County (Portland)
261
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's Multnomah County (Portland) Projection as of 2020-04-01
Initial doubling: 1.7 days, Predicted peak: 599
7

8. Westchester County
12,258
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's Westchester County Projection as of 2020-04-01
Initial doubling: 2.0 days, Predicted peak: 12,990
8

9. Alameda County
473
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's Alameda County Projection as of 2020-04-01
Initial doubling: 2.6 days, Predicted peak: 623
9

10. Orleans Parish
3,374
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's Orleans Parish Projection as of 2020-04-01
Initial doubling: 2.4 days, Predicted peak: 13,938
10

11. Bay Area
2,970
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's Bay Area Projection as of 2020-04-01
Initial doubling: 2.6 days, Predicted peak: 10,350
11

12. California
17,462
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's California Projection as of 2020-04-01
Initial doubling: 3.0 days, Predicted peak: 104,119
12

13. Utah
1,816
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
Date
Actual(points)/Predicted(line)
Phase
Pre log linear
Log linear
Social distancing
Steve's Utah Projection as of 2020-04-01
Initial doubling: 1.7 days, Predicted peak: 5,474
13

14. Doubling Time
Overall US: 4.2 days
0
2
4
6
State
DoublingTime
Steve's 7 day estimation of doubling time 2020-04-01
14

15. Doubling Time
3.0
4.0
5.0
6.0
Doubling Time
Steve's 7 day estimation of doubling time 2020-04-01
15

16. All states in 1 week
Overall US: 20.4 cases
0
40
80
120
State
Casesper10,000in1week
Steve's projection for 2020-04-07
16

17. Projected Cases per 10,000
25
50
75
100
Cases Per 10000
Steve's projection for 2020-04-07
17