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- Sherratt, K., et al.
(författare)
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Predictive performance of multi-model ensemble forecasts of COVID-19 across European nations
- 2023
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Methods: We used open-source tools to develop a public European COVID-19 Forecast Hub. We invited groups globally to contribute weekly forecasts for COVID-19 cases and deaths reported by a standardised source for 32 countries over the next 1–4 weeks. Teams submitted forecasts from March 2021 using standardised quantiles of the predictive distribution. Each week we created an ensemble forecast, where each predictive quantile was calculated as the equally-weighted average (initially the mean and then from 26th July the median) of all individual models’ predictive quantiles. We measured the performance of each model using the relative Weighted Interval Score (WIS), comparing models’ forecast accuracy relative to all other models. We retrospectively explored alternative methods for ensemble forecasts, including weighted averages based on models’ past predictive performance.Results: Over 52 weeks, we collected forecasts from 48 unique models. We evaluated 29 models’ forecast scores in comparison to the ensemble model. We found a weekly ensemble had a consistently strong performance across countries over time. Across all horizons and locations, the ensemble performed better on relative WIS than 83% of participating models’ forecasts of incident cases (with a total N=886 predictions from 23 unique models), and 91% of participating models’ forecasts of deaths (N=763 predictions from 20 models). Across a 1–4 week time horizon, ensemble performance declined with longer forecast periods when forecasting cases, but remained stable over 4 weeks for incident death forecasts. In every forecast across 32 countries, the ensemble outperformed most contributing models when forecasting either cases or deaths, frequently outperforming all of its individual component models. Among several choices of ensemble methods we found that the most influential and best choice was to use a median average of models instead of using the mean, regardless of methods of weighting component forecast models.Conclusions: Our results support the use of combining forecasts from individual models into an ensemble in order to improve predictive performance across epidemiological targets and populations during infectious disease epidemics. Our findings further suggest that median ensemble methods yield better predictive performance more than ones based on means. Our findings also highlight that forecast consumers should place more weight on incident death forecasts than incident case forecasts at forecast horizons greater than 2 weeks.
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| 2. |
- Bock, Wolfgang, et al.
(författare)
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Testing, social distancing and age specific quarantine for COVID-19 : Case studies in Iligan City and Cagayan de Oro City, Philippines
- 2020
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Ingår i: 9th Jagna International Workshop Stochastic Analysis – Mathematical Methods and Real-World Models, 8–18 January 2020, Bohol, Philippines. - : American Institute of Physics (AIP). - 9780735440166
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Konferensbidrag (refereegranskat)abstract
- The world today grapples with the health crisis caused by the novel COVID-19. Unfortunately, the Philippines, which was spared from the previous epidemics like Ebola and SARS, is now facing this major obstacle. The local government units of the country responded by issuing guidelines to mitigate the spread of infection. Two neighboring cities in the Philippines, namely, Iligan and Cagayan de Oro have been the focus of this study. Simulations have been undertaken to investigate the prevalence of the disease and the health care systems capacity to accommodate critically ill patients over time. The effects of mitigating strategies like social distancing, age specific quarantine and testing were considered. The model used for the spread of COVID-19 is an individual-based SIR model. The results indicated that social distancing and age specific quarantine can effectively slow down the progression of the disease. Moreover, social distancing combined with an effective testing strategy can keep the epidemic subcritical.
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