indic {EVI}

Issue of an Early Warning

Description

This secondary function produces the early warning signal (Index).

Usage

indic(evi = NA, cevi = NA, cut = NA, cases, method = "EVI")

Arguments

evi

numeric vector - object (obtained from the evi function and stored as ev) that corresponds to the relative change in the standard deviation.

cevi

numeric vector - object (obtained from the cevi function and stored as cev) that corresponds to a positive and negative test.

cut

threshold value (0 <= c <= 0.5) for issuing an early warning. If evi >= c an early warning is issued and otherwise is not.

cases

numeric vector with the number of new cases per unit of time (i.e., daily).

method

either "EVI" or "cEVI", default equals to "EVI".

Value

A vector of 0s and 1s is produced, where a 1 (Index = 1) is recorded when an early warning is issued and a 0 (Index = 0) when an early warning is not issued.

References

Kostoulas P, Meletis E, Pateras K, et al. The epidemic volatility index, a novel early warning tool for identifying new waves in an epidemic. Sci Rep 11, 23775 (2021). doi:10.1038/s41598-021-02622-3 Pateras K, Meletis E, Denwood M, et al. The convergence epidemic index (cEVI) an early warning tool for identifying waves in an epidemic. Inf Dis Mod, (2023)

Examples

## EVI example ##

data("Italy")
cases = mova(cases = Italy$Cases, r_a = 7)
roll = rollsd(cases = cases, lag_t = 7)
ev = evi(rollsd = roll)
ind=indic(evi = ev, cut = 0.01, cases = cases)