Modified the short-term model to allow for (slowly changing) seasonality.
Many countries show clear seasonality after
the initial period, likely caused by institutional factors regarding data collection.
This seasonality was also getting in the way of peak detection. As a consequence estimates of the peak date may have changed
for countries with strong seasonality.
of cumulative confirmed cases for lower tier local authorities of England
The data is available from 2020-07-02 including all tests (pillar one and two).
Only authorities with more than 5 cases in the previous week are included.
Tables in April included the world, but not the world as we know it (double counting China and the US). So removed the world from those old tables.
Why short-term forecasts can be better than models for predicting how pandemics evolve
just appeared at The Conversation
Thursday 2 July webinar at the FGV EESP - São Paolo School of Economics. This starts at 16:00 UK time (UTC+01:00)
and streamed here
on short-term COVID-19 forecasting
on 26 June (14:00 UK time) at the Quarterly Forecasting Forum of the IIF UK Chapter.
Removed Brazil from yesterday's forecasts (only; last observation 2020-06-05).
Data issues with confirmed cases for France.
Added an appendix to the short term paper
with further forecast
comparisons for European and Latin American countries.
Both Sweden and Iran have lost their peak in confirmed cases. For Sweden the previous peak was on 24 April (daily peak of 656 cases), for Iran it was
on 31 March (peak of 3116). For Iran this looks like a second wave, with increasing daily counts for the last four weeks.
For Sweden this is a sudden jump in confirmed cases in the last two days, compared to a fairly steady
weekly pattern over the previous six weeks.
Problem with UK confirmed cases: negative daily count. This makes the forecasts temporarily unreliable.
Updated the second paper
Minor fixes to the improved version of scenario forecasting, backported to 2020-05-13.
We now omit countries with fewer than 200 confirmed cases in the last week (25 for deaths).
The short-term paper has some small updates, including further comparisons with other models.
Data for Ecuador are not reliable enough for forecasting.
Switched to an improved version of scenario forecasting.
The New York Times is in the process of redefining its US state data. Unfortunately, at the moment only the last observation has changed
(e.g New York deaths jumped from 19645 on 2020-05-05 to 25956 a day later). This means the data is currently useless; however it does bring it close
to the Johns Hopkins/CSSE count (25626 on 2020-05-06). The aggregate US count is based on JH/CSSE so unaffected.
We now use Johns Hopkins/CSSE US state data, including all states with sufficient counts. So the new forecasts cannot be compared to those previously.
A minor change is that we show the graph without scenario forecast if no peak has been detected yet.
See our blog entry at the
International Institute of Forecasters
US history of death counts revised in Johns Hopkins/CSSE data.
UK death counts have been revised to include the deaths in care homes.
In the Johns Hopkins/CSSE data set, which we use, the entire history has been revised. So forecasts made up to 2020-04-29
cannot be compared to later outcomes.
In the ECDC data set only the last observation has changed, causing a jump in the series.
Our short-term COVID-19 forecasting paper is now available as
Nuffield Economics Discussion Paper 2020-W06
A small adjustment has been made to the scenario forecast methodology, and will be documented shortly.
A summary of our work on short-term COVID-19 forecasting appeared as a voxeu
Bird and Nielsen
look into nowcasting death counts in England.
[2020-04-16] Added scenario forecasts to all graphs now. This would now be the preferred forecast for most.
This is the first time with a peak in confirmed UK cases
(also for deaths, but this is uncertain because it is at the same date).
[2020-04-10] Updated documentation with better description of short-term estimates and peak determination.
[2020-04-09] Added table with estimated peak dates (if happened) and dates to and since the peak. Note that this
can be a local peak, and subsequent re-acceleration (or data revisions) can result in a new peak later.
[2020-04-08] Minor correction to peak estimates. Added table with scenario forecasts.
[2020-04-06] Added a post hoc estimate of the peak number of cases. This needs at least three confirmed observations (four for deaths)
after the event. It is based on the averaged smooth trend, and can change later or be a local peak. It is marked with a vertical line
with the date label, or a date with left arrow in the bottom left corner of the graph. This is backported to 2020-04-04.
[2020-04-02] Now including more US States, based on New York Times data.
[2020-03-31] Scenario forecasts, based on what happened in China earlier this year, are presented for several countries (line marked with x).
Created more plausible 90% confidence bands (dotted line in same colour).
[2020-03-26] Scenario forecasts that are based on what happened in China earlier this year, only for Italy.
[2020-03-24] Our forecasts are starting to overestimate in some cases. This was always expected to happen when the increase starts
to slow down. Scenario forecasts that are based on what happened in China earlier this year, but only for Italy and Spain sofar.