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. 2021 Sep 9;15(9):e0009653. doi: 10.1371/journal.pntd.0009653

Table 4. Model applications.

Only published model applications were included. Each line corresponds to a separate model test; therefore, some models appear more than once. References are listed for further details.

Model Study Prediction Target Sample Size Spatial Domain Time Domain Testing Method1 Metric Score2
B. Spatial Risk Random Forest [29] Mean annual incidence per 100,000 population 43,512 county-years Conterminous US (3,108 counties) 2005–2018, averaged Bootstrapping R2pred = 0.59 [0.44–0.70], RMSE = 3.7
D. Spatial Risk High Resolution BRT [30] Ranked relative risk (0–1) 1,378 human cases South Dakota 2004–2017 Out of sample data AUC = 0.727
E. RF1 [28] Annual human cases 882 county-years New York and Connecticut 2000–2015 LOYOCV R2pred = 0.72, RMSE = 1.6
E. RF1 [28] Seasonal mosquito MLE 218 county-years New York and Connecticut 2000–2015 LOYOCV R2pred = 0.45, RMSE = 2.3
E. RF1 [28] Seasonal mosquito MLE 2,596 trap-years New York and Connecticut by trap 2000–2015 LOYOCV R2pred = 0.53, RMSE = 1.0
F. NE_WNV County-years [34] 2018 human cases3 1,472 county-years Nebraska 2002–2017 Out of sample data CRPS = 1.90
F. NE_WNV County-years [34] 2018 WNV positive counties3 1,472 county-years Nebraska 2002–2017 Out of sample data Accuracy = 0.717
G. GLMER Ensemble [20] MLE mosquito infection rate 225 grid-years Suffolk County, New York 2001–2015 LOYOCV RMSE = 4.27
H. Harris County [21] MLE mosquito infection rate (1-month lead) 130,567 trap-nights Harris County, Texas 2002–2016 Out of sample data R2pred = 0.8
H. Harris County [21] Mosquito abundance (1-month lead) 10,533,033 mosquitoes Harris County, Texas 2002–2016 Out of sample data R2pred = 0.2
I. ArboMAP [35] Positive county-weeks Approximately 9,504 county-weeks (training)
Approximately 792 county-weeks (testing)
South Dakota 2004–2015 (training) 2016 (testing) Out of sample data AUC = 0.836–0.8564
I. ArboMAP [36] Positive county-weeks Approximately 11,088 county-weeks South Dakota 2004–20175 Fit to training data only AUC = 0.876, Rs = 0.84
J. Chicago Ultra-Fine Scale [2224] Human case probability (by hexagon) 1,346,940 hexagon-weeks Variable, up to 5,345 1-km hexagons 2005–20166 Fit to training data only R2 > 0.85; RMSE < 0.02; AUC > 0.90
K. Model-EAKF System [25] Annual human cases; peak mosquito infection rates; peak timing of infectious mosquitoes; annual infectious mosquitoes 21 county-years 2 counties (Suffolk, New York and Cook, Illinois) Weekly, Varied by location Retrospective data assimilation Threshold-based accuracy 7
K. Model-EAKF System [26] Multiple8 110 outbreak-years 12 counties Weekly, Varied by location Retrospective data assimilation Threshold-based accuracy 7
K. Model-EAKF System [39] Multiple8 4 county-years 4 counties Weekly, 2017 Real-time data assimilation Threshold-based accuracy 7
L. Temperature-forced Model-EAKF System [26] Multiple8 110 outbreak- years 12 counties Weekly, Varied by location Retrospective data assimilation
Threshold-based accuracy 7
M. California Risk Assessment [31] Historical outbreaks of western equine encephalomyelitis and St. Louis encephalitis as proxy for WNV 14 agency-years California Half-months Temporal correspondence Early detection of arbovirus risk prior to outbreaks
M. California Risk Assessment [32] Onset and peak of human cases by geographic region 12 half-months in 3 regions California Half-months Retrospective data assimilation Early detection of WNV risk prior to onset and peak of human cases
M. California Risk Assessment [33] Emergency planning threshold (risk ≥ 2.6) 11,476 trap-nights Los Angeles Country, California 2004–2010 Retrospective data assimilation AUC = 0.982

1LOYOCV: leave-one-year-out cross-validation; Out of sample data: accuracy based on data not used to develop the model; Fit to training data only: accuracy based on the same data used to develop the model; Retrospective data assimilation: finalized data until the time of forecast; Real-time data assimilation: data processed and available at the time of forecast.

2R2pred: predictive R2, i.e., an R2 calculated on data outside the sample, Rs: Spearman correlation coefficient, AUC: area under the curve, Threshold-based accuracy: +/−25% of peak week, human cases, total infections over the season; +/−25% or 1 human case, RMSE: Root Mean Squared Error, CRPS: Continuous Ranked Probability Score.

3Results for 2018 reported here, validation was also performed separately for 2012–2017, see [34] for details.

4Three analyses presented: short-term: AUC = 0.856, annual made on July 5: AUC = 0.836, annual made on July 39: AUC = 0.855.

5Restricted to July–September for each year.

6Restricted to 21 epi weeks per year.

7Varied by analysis and lead time.

8Prediction targets: human cases in next 3 weeks; annual human cases; week with highest percentage of infectious mosquitoes; peak mosquito infection rate; annual infectious mosquitoes.

AUC, area under the curve; CRPS, Continuous Ranked Probability Score; LOYOCV: leave-one-year-out cross-validation; RMSE, Root Mean Squared Error; WNV, West Nile virus.