evifcut {EVI}

Sensitivity-Specificity estimation for each cut-off value and rolling window size

Description

This function calculates the sensitivity and the specificity for each cut-off value and rolling window size.

Usage

evifcut(evi = NA, cevi = NA, cases, cut = NA, r, 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 either a positive or negative test.

cases

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

cut

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

r

Definition for the minimum difference in the mean number of cases, one week before and after each time point that, if present, should be detected. This is the case definition and the default is 0.2 (with 0 <= r <= 1). A value of r=0.2 means that we have a case when the mean number of the newly observed cases in the next 7 days is at least 20% higher than the mean number of the newly observed cases in the past 7 days.

method

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

Value

Returns a list of the estimated Sensitivity, Specificity, apparent and true prevalence for each cut-off value and rolling window size

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)
#roll = rollsd(cases = cases,lag_t = 7)
#ev = evi(rollsd = roll)
#evifcut(evi = ev, cases = cases, cut = 0.01, r = 0.2)