Evaluating probabilistic dengue risk forecasts from a prototype early warning system for Brazil
- Institut Català de Ciències del Clima, Spain
- Instituto Nacional de Pesquisas Espaciais, Brazil
- Fundação Oswaldo Cruz, Brazil
- Universidade Estadual Paulista, Brazil
- Ministério da Saúde, Brazil
- Universidade de Brasília, Brazil
- University of Exeter, United Kingdom
- Institució Catalana de Recerca i Estudis Avançats, Spain
Figures
Figure 1
Predictive distributions and observed DIR for June 2014 for host microregions.
Posterior predictive distributions of dengue incidence rates (DIR) (base-10 logarithmic scale) for June 2014 showing the probability of low risk (blue), medium risk (orange) and high risk (pink) for …
Figure 2
Probabilistic dengue forecast and observed dengue incidence rate categories for Brazil, June 2014.
(a) Probabilistic dengue forecast for June 2014. The continuous colour palette (ternary phase diagram) conveys the probabilities assigned to low-risk, medium-risk, and high-risk dengue categories. …
Figure 3
Forecast probability of observed DIR categories for June 2014.
Probability of observing the correct DIR category (low, medium and high). The graduated colour bar represents the probability of observing any given category (ranging from 0%, pale colours, to 100%, …
Figure 4
Forecast probability of observed DIR in the low, medium and high category for June 2014.
Forecast probability given that (a) low, (b) medium and (c) high DIR was observed. Grey areas indicate that other DIR categories were observed and are therefore not considered. The graduated colour …
Figure 5
Hit rate and false alarm rate for predicting dengue in the high risk category for June 2000–2014 using the forecast model and null model.
Comparison of (a) hit rates and (b) false alarm rates for the event of observed DIR exceeding the high risk epidemic threshold (300 cases per 100,000 inhabitants) using the probabilistic category …
Figure 6
Time series of observed and predicted DIR for June 2000–2014 for host microregions.
Observed DIR (pink squares), posterior mean DIR (blue circles) and upper 95% prediction (credible) interval from forecast model (blue dashed line) and mean DIR (orange triangles) and upper 95% …
Author response image 1
Dengue incidence and number of municipalities reporting dengue cases in Brazil, 1985-2010 (Source: Barreto et al., 2011).
https://doi.org/10.7554/eLife.11285.012Tables
Table 1
Dengue risk forecast warnings and corresponding observations for June, 2014 for host microregions. Dengue risk forecast warnings and observed category for June 2014, for the microregions hosting the …
| Microregion | Forecast warning | Probability (pL, pM, pH) | Observed DIR | Observed category |
|---|---|---|---|---|
| Belo Horizonte | Medium | p(65%, 24%, 11%) | 126 | Medium |
| Brasília | Low | p(73%, 20%, 7%) | 725 | High |
| Cuiabá | Low | p(71%, 22%, 7%) | 168 | Medium |
| Curitiba | Low | p(100%, 0%, 0%) | 4 | Low |
| Fortaleza | High | p(34%, 20%, 46%) | 507 | High |
| Manaus | Medium | p(63%, 25%, 12%) | 110 | Medium |
| Natal | High | p(32%, 20%, 48%) | 780 | High |
| Porto Alegre | Low | p(100%, 0%, 0%) | 1 | Low |
| Recife | High | p(57%, 24%, 19%) | 161 | Medium |
| Salvador | Medium | p(56%, 27%, 17%) | 149 | Medium |
| São Paulo | Low | p(99%, 1%, 0%) | 161 | Medium |
| Rio de Janeiro | Medium | p(62%, 25%, 13%) | 32 | Low |
Table 2
Summary of contingency table results for observed DIR exceeding the epidemic risk threshold. Summary of contingency table results for observed DIR exceeding the high risk epidemic threshold (300 …
| Performance measures | Forecast model probabilistic | Null model seasonal mean |
|---|---|---|
| Hit | 81 | 46 |
| False alarm (type I error) | 94 | 55 |
| Miss (type II error) | 60 | 95 |
| Correct rejection | 318 | 357 |
| Hit rate | 57% | 33% |
| False alarm rate | 23% | 13% |
| Miss rate | 43% | 67% |
Table 3
The four possible outcomes for categorical forecasts of a binary event.
Event observed | ||||
|---|---|---|---|---|
| Yes | No | Total | ||
Forecast warning issued | Yes | Hit (a) | False alarm (b) | a+b |
| No | Miss (c) | Correct rejection (d) | c+d | |
| Total | a+c | b+d | a+b+c+d=n | |
