COVID-19 short-term forecasts Confirmed 2020-06-12


Disclaimer

  • Forecasts produced by Jennie Castle, Jurgen Doornik, and David Hendry, researchers at the University of Oxford. These are our forecasts, and should not be considered official forecasts from, or endorsed by, any of: University of Oxford, Oxford Martin School, Nuffield College, or Magdalen College.
  • These forecasts are short term time-series extrapolations of the data. They are not based on epidemiological modelling or simulations. The documentation that is provided is still in progress and not peer reviewed. All forecasts are uncertain: their success can only be determined afterwards. Many mitigation strategies are in place, which, if successful, invalidate our forecasts. An explanation of our methods is provided below.

Recent changes

[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.
[2020-03-26] Scenario forecasts that are based on what happened in China earlier this year, only for Italy.
[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).
[2020-04-02] Now including more US States, based on New York Times data. And the world.
[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.
[2020-04-08] Minor correction to peak estimates. Added table with scenario forecasts.
[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.
[2020-04-10] Updated documentation with better description of short-term estimates and peak determination.
[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).
[2020-04-17] Bird and Nielsen look into nowcasting death counts in England.
[2020-04-24] A summary of our work on short-term COVID-19 forecasting appeared as a voxeu.
[2020-04-27] 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.
[2020-04-29] 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.
[2020-05-06] 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.
[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.
[2020-05-18] Minor fixes to the improved version of scenario forecasting, backported to 2020-05-13.
[2020-05-20] Problem with UK confirmed cases: negative daily count. This makes the forecasts temporarily unreliable.
Updated the second paper.
[2020-06-04] 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.
[2020-06-06] Removed Brazil from yesterday's forecasts (last observation 2020-06-05).

Further information

  • We believe these forecasts fill a useful gap in the short run. They give an indication of what is likely to happen in the next few days, removing some aspect of surprise. Moreover, a noticeable drop in comparison to the extrapolations could be an indication that the implemented policies are having some impact. It is difficult to understand exponential growth. We hope that these forecasts may help to convince viewers to adhere to the policies implemented by their respective governments, and keep all arguments factual and measured.
  • We use the data repository for the 2019 Novel Coronavirus Visual Dashboard operated by the Johns Hopkins University Center for Systems Science and Engineering. This is updated daily, but we tend to update our forecasts only every other day.
    US state data as of 2020-03-28 is courtesy of the New York Times.
  • We can only provide forecasts of what is measured. If confirmed cases are an underestimate of actual cases, then our forecasts will also be underestimates. No other epidemiological data is used. Data definition and collection differs between countries and may change over time.
  • We will update the methodology as we learn what is happening in the next few days or weeks. Once the number of cases levels off, there is no need to provide these forecasts anymore.
  • Countries where the counts are very low or stable have been omitted.
  • The graphs have dates on the horizontal axis (yyyy-mm-dd) and cumulative counts on the vertical axis. They show
    1. bold dark grey line (with circles): observed counts (Johns Hopkins CSSE);
    2. many light grey lines (with open circles): forecasts using different model settings and starting up to four periods back;
    3. red line (with open circles): single forecasts path using default model settings;
    4. black line (with crosses): average of all forecasts, recentered on the last observation;
    5. thin green lines: some indication of uncertainty around the red forecasts, but we do not know how reliable that is.
    Both the red line forecasts and the black lines are also given in the tables above. These forecasts differ, we are currently inclined to use the average forecasts.
  • The forecasts are constructed as follows:
    1. An overall `trend' is extracted by taking a window of the data at a time. In each window we draw `straight lines' which are selected using an automatic econometric procedure (`machine learning'). All straight lines are collected and averaged, giving the trend.
    2. Forecasts are made using the estimated trend, but we note that this must be done carefully, because simply extrapolating the flexible insample trend would lead to wildly fluctuating forecast. We use the `Cardt' method, which has been found to work well in other settings.
    3. Residuals from the trend are also forecast, and combined with trend forecasts into an overall forecast.
  • Scenario forecasts are constructed very differently: smooth versions of the Chinese experience are matched at different lag lengths with the path of each country. This probably works best from the peak, or the slowdown just before (but we include it for the UK nonetheless).
  • The forecast evaluation shows past forecasts, together with the outcomes (in the grey line with circles).
  • EU-BS is Estonia, Latvia, and Lithuania together.
  • This paper describes the methodology and gives further references. Also available as Nuffield Economics Discussion Paper 2020-W06. Still preliminary is the documentation of the medium term forecasts.

Confirmed count average forecast Latin America (bold black line in graphs) 2020-06-13 to 2020-06-19

DateArgentinaBoliviaBrazilChileColombiaDominican RepublicEcuadorEl SalvadorGuatemalaHaitiHondurasMexicoPanamaPeruVenezuela
2020-06-12 28764 16929 828810 160846 45344 22008 45778 3481 8982 3941 8132 139196 19211 214788 2879
2020-06-13 29900 17400 865000 167000 45800 22600 45900 3580 9400 4050 8400 145000 19700 217000 2960
2020-06-14 31300 18200 908000 175000 46600 23300 46200 3680 9800 4210 8700 151000 20400 221000 3060
2020-06-15 32800 19000 953000 183000 47500 24100 46500 3790 10300 4370 9200 158000 21100 224000 3160
2020-06-16 34400 19900 1001000 191000 48600 24800 46900 3910 10800 4540 9600 164000 21800 227000 3260
2020-06-17 36000 20800 1051000 199000 49700 25600 47200 4030 11300 4720 10000 171000 22600 231000 3370
2020-06-18 37700 21700 1103000 208000 50900 26400 47700 4150 11800 4910 10500 179000 23400 234000 3480
2020-06-19 39500 22700 1158000 218000 52100 27200 48100 4270 12400 5100 11000 186000 24200 238000 3600

Confirmed count forecast Latin America (bold red line in graphs) 2020-06-13 to 2020-06-19

DateArgentinaBoliviaBrazilChileColombiaDominican RepublicEcuadorEl SalvadorGuatemalaHaitiHondurasMexicoPanamaPeruVenezuela
2020-06-12 28764 16929 828810 160846 45344 22008 45778 3481 8982 3941 8132 139196 19211 214788 2879
2020-06-13 30300 17800 866000 169000 46300 22700 46100 3590 9400 4050 8600 145000 19800 217000 2950
2020-06-14 31900 18600 905000 177000 47400 23500 46600 3700 9900 4130 9200 150000 20500 219000 3010
2020-06-15 33600 19600 946000 185000 48600 24300 47100 3810 10300 4220 9700 156000 21300 221000 3080
2020-06-16 35300 20500 990000 194000 49800 25100 47600 3930 10800 4300 10400 163000 22000 224000 3150
2020-06-17 37200 21500 1036000 204000 51000 25900 48100 4050 11400 4390 11000 169000 22800 226000 3220
2020-06-18 39100 22600 1084000 213000 52300 26800 48700 4170 11900 4470 11700 176000 23600 228000 3290
2020-06-19 41100 23700 1135000 224000 53600 27700 49200 4300 12500 4560 12400 183000 24400 230000 3360

Confirmed count scenario forecast (bold purple line in graphs) 2020-06-13 to 2020-06-21

DateArgentinaBoliviaBrazilChileColombiaDominican RepublicEcuadorEl SalvadorGuatemalaHaitiHondurasMexicoPanamaPeruVenezuela
2020-06-12 28764 16929 828810 160846 45344 22008 45778 3481 8982 3941 8132 139196 19211 214788 2879
2020-06-13 29600 17300 860000 165000 46200 22300 45800 3510 9300 4110 8400 143000 19600 219000 3000
2020-06-14 30600 18100 888000 169000 47600 22700 46100 3600 9600 4230 8800 146000 20100 222000 3100
2020-06-15 31300 18500 917000 174000 48700 23000 46200 3640 9900 4360 9100 148000 20600 226000 3200
2020-06-16 32600 19400 945000 178000 49900 23200 46400 3710 10200 4500 9400 151000 21000 228000 3300
2020-06-17 33200 19800 969000 182000 51500 23200 46700 3730 10400 4640 9700 152000 21400 231000 3430
2020-06-18 34400 20200 992000 185000 52700 23300 46800 3770 10600 4730 9900 153000 21900 233000 3540
2020-06-19 35100 21000 1015000 190000 53400 23300 46900 3790 10900 4860 10200 156000 22100 236000 3660
2020-06-20 35600 21600 1035000 194000 54500 23400 47000 3830 11100 4960 10500 158000 22400 237000 3790
2020-06-21 36300 22100 1052000 198000 55600 23600 47100 3860 11300 5080 10700 160000 22800 238000 3880

Peak increase in estimated trend of Confirmed in Latin America 2020-06-12

ArgentinaBoliviaBrazilChileColombiaDominican RepublicEcuadorEl SalvadorGuatemalaHaitiHondurasMexicoPanamaPeruVenezuela
Peak date -- -- -- --06-05 --04-24 -- --06-06 -- -- --05-3006-04
Peak daily increment 1773 3950 211 6774 129
Days from 100 to peak 78 37 32 74 70
Days from peak/2 to peak 66 25 31 52 74
Last total 28764 16929 828810 160846 45344 22008 45778 3481 8982 3941 8132 139196 19211 214788 2879
Last daily increment 1391 764 25982 6754 1534 571 1338 108 421 0 463 5222 625 0 65
Last week 6744 3571 155964 33101 8585 2813 3050 547 2190 869 1977 25577 3207 23030 563
Days since peak 7 49 6 13 8

Initial visual evaluation of forecasts of Confirmed