COVID-19 short-term forecasts Confirmed 2020-06-05


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 The documentation that is provided is still in progress and not peer reviewed.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.

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) 2020-06-06 to 2020-06-12

DateArgentinaBoliviaBrazilChileColombiaDominican RepublicEcuadorEl SalvadorGuatemalaHaitiHondurasMexicoPanamaPeruVenezuela
2020-06-05 21037 12728 122499 36759 18708 41575 2849 6485 2740 5971 110026 15463 187400 2145
2020-06-06 21900 13200 126000 37400 18800 41900 2900 6580 2840 6070 115000 16000 191000 2270
2020-06-07 23000 13800 130000 39100 19000 42300 2960 6780 2960 6200 120000 16500 195000 2400
2020-06-08 24000 14300 135000 41200 19200 42700 3030 7040 3080 6330 126000 17100 199000 2540
2020-06-09 25200 15000 140000 43400 19500 43100 3100 7290 3220 6470 131000 17700 203000 2690
2020-06-10 26400 15600 144000 45700 19700 43600 3170 7560 3370 6610 138000 18400 208000 2850
2020-06-11 27600 16300 150000 48100 20000 44000 3240 7850 3540 6760 144000 19000 213000 3020
2020-06-12 28900 17000 155000 50600 20300 44400 3310 8150 3720 6910 151000 19700 218000 3200

Confirmed count forecast Latin America (bold red line in graphs) 2020-06-06 to 2020-06-12

DateArgentinaBoliviaBrazilChileColombiaDominican RepublicEcuadorEl SalvadorGuatemalaHaitiHondurasMexicoPanamaPeruVenezuela
2020-06-05 21037 12728 122499 36759 18708 41575 2849 6485 2740 5971 110026 15463 187400 2145
2020-06-06 22000 13200 126000 39000 18900 42000 2910 6750 2870 6110 115000 16000 192000 2310
2020-06-07 23000 13700 131000 41700 19200 42400 2960 7020 2990 6240 120000 16500 197000 2450
2020-06-08 24100 14200 135000 44500 19500 42900 3020 7320 3110 6380 126000 17100 202000 2580
2020-06-09 25200 14700 139000 47400 19700 43300 3080 7620 3230 6510 131000 17700 207000 2720
2020-06-10 26300 15300 144000 50600 20000 43800 3140 7930 3360 6660 137000 18300 212000 2870
2020-06-11 27500 15900 148000 53900 20300 44200 3200 8260 3480 6800 144000 18900 217000 3020
2020-06-12 28800 16500 153000 57500 20600 44700 3260 8600 3610 6950 150000 19600 222000 3190

Confirmed count scenario forecast (bold purple line in graphs) 2020-06-06 to 2020-06-14

DateArgentinaBoliviaBrazilChileColombiaDominican RepublicEcuadorEl SalvadorGuatemalaHaitiHondurasMexicoPanamaPeruVenezuela
2020-06-05 21037 12728 122499 36759 18708 41575 2849 6485 2740 5971 110026 15463 187400 2145
2020-06-06 21800 13200 127000 37800 18900 41800 2900 6680 2880 6150 114000 15800 195000 2330
2020-06-07 22600 13700 132000 39200 19100 42200 2960 6950 3020 6320 117000 16200 199000 2470
2020-06-08 23500 14100 136000 40400 19300 42600 3000 7200 3160 6490 121000 16500 206000 2660
2020-06-09 24200 14700 140000 41600 19500 42800 3070 7440 3280 6660 125000 16800 212000 2810
2020-06-10 24900 15200 144000 42700 19800 43100 3120 7680 3420 6850 128000 17200 218000 2890
2020-06-11 25500 15700 147000 43700 20200 43300 3180 7890 3530 7020 131000 17400 224000 3000
2020-06-12 26100 16300 151000 45200 20300 43500 3210 8090 3670 7200 133000 17700 230000 3120
2020-06-13 26700 16800 154000 46000 20600 43600 3240 8260 3780 7410 136000 18000 235000 3270
2020-06-14 27200 17400 157000 47200 20800 43700 3290 8430 3890 7670 139000 18100 241000 3360

Peak increase in estimated trend of Confirmed in Latin America 2020-06-05

ArgentinaBoliviaBrazilChileColombiaDominican RepublicEcuadorEl SalvadorGuatemalaHaitiHondurasMexicoPanamaPeruVenezuela
Peak date --05-30 --05-31 --05-2904-2405-30 --05-3005-24 -- --05-30 --
Peak daily increment 607 4500 384 3949 94 207 252 6989
Days from 100 to peak 60 76 69 37 51 25 56 74
Days from peak/2 to peak 48 62 67 25 56 24 55 52
Last total 21037 12728 614941 122499 36759 18708 41575 2849 6485 2740 5971 110026 15463 187400 2145
Last daily increment 840 483 0 4207 3293 389 609 68 331 100 91 4346 419 4202 58
Last week 4823 3136 116501 27641 10025 1800 3004 454 1746 875 877 22514 2445 31729 686
Days since peak 6 5 7 42 6 6 12 6

Initial visual evaluation of forecasts of Confirmed