# calculate_I_mixed: Function to calculate incidence from PPS data using a mix of... In prevtoinc: Prevalence to Incidence Calculations for Point-Prevalence Studies in a Nosocomial Setting

## Description

A sigmoid function with parameters a and b (see below) is used to get weights for a combination of the two estimator for x.loi and x.los.

## Usage

 ```1 2``` ```calculate_I_mixed(I.pps.1, I.pps.2, a = 0.01, b = 500, method = "pps.mixed") ```

## Arguments

 `I.pps.1` resulting data frame for first estimator `I.pps.2` resulting data frame for second estimator `a` parameter a for the sigmoid function `b` parameter b for the sigmoid function `method` name of the method

## Details

is achieved in the following way for estimation of x.loi alpha = exp(a*(n.noso-b))/(1+exp(a*(n.noso-b))) x.loi.hat.mixed = alpha*x.loi.hat.1 + (1-alpha)*x.loi.hat.2

alpha = exp(a*(n-b))/(1+exp(a*(n-b))) x.los.hat.mixed = alpha*x.los.hat.1 + (1-alpha)*x.los.hat.2

## Value

one-row data frame with following columns

• n - number of patients sampled

• n.noso - number of HAIs

• P.hat - estimate of prevalence P

• I.hat - estimate of incidence rate I

• I.pp.hat - estimate of incidence proportion per admission I.pp

• x.loi.hat - estimate of x.loi

• x.los.hat - estimate of x.los

• method - name of the method

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21``` ```# create example data for PPS example.dist <- create_dist_vec(function(x) dpois(x-1, 7), max.dist = 70) example.dist.los <- create_dist_vec(function(x) dpois(x-1, lambda = 12), max.dist = 70) data.pps.fast <- simulate_pps_fast(n.sample=200, P=0.05, dist.X.loi = example.dist, dist.X.los = example.dist.los) head(data.pps.fast) # estimate of incidence I.1 <- calculate_I_smooth(data = data.pps.fast, method = "gren") # estimate incidence based on Rhame-Sudderth formula I.2 <- calculate_I_rhame(data = data.pps.fast, x.loi.hat = 8, x.los.hat = 13) # mixed estimator calculate_I_mixed(I.1, I.2) ```

prevtoinc documentation built on June 18, 2019, 5:05 p.m.