arse {arse}

Calculates the area of resilience to stress event below a baseline.

Description

This function takes a series of 'x,y' coordinates and a specified 'y' baseline value. For a given set of x-coordinates over time and repeated measures of a 'y' variable, this function calculates the area of resilience to a stress event (arse) that is formed below the specified baseline value of 'y' using an implementation of the shoelace formula (Gauss's area formula) for the area of irregular polygons. Any area above the baseline (i.e., growth) is ignored. Smaller arse values are indicative of better resilience on the measured variable.

Usage

arse(data, xcoord, ycoord, ybase = NA, yinvert = FALSE,
  saveout = FALSE)

Arguments

data

A dataframe with x- and y-coordinates in wide format.

xcoord

A specified selection of the x-coordinate values within the dataframe. The first x-coordinate value should correspond to the baseline input of 'y'.

ycoord

A specified selection of the y-coordinate values within the dataframe. The first y-coordinate value should correspond to the baseline value of 'y'. The second y-coordinate value should be the first measure of 'y' after the intrusion of a stress event. The last value of 'y' should correspond to the last measurement of 'y' over the measured timeframe.

ybase

A specified selection of the baseline of the 'y' measured variable. Users are advised to place baseline as the first instance of the y-coordinate values. Function defaults to use the first y-coordinate value in the series.

yinvert

Specifies whether resilience occurs above or below the baseline depending on the meaning of high and low 'y' values. When parameter 'yinvert' is set to 'FALSE' (the default), it is assumed that higher numbers are indicative of positive (i.e., desired) 'y' values (e.g., exam grade). When 'yinvert' is set to 'TRUE', it is assumed that lower numbers are indicative of positive (i.e., desired) 'y' values (e.g., blood pressure).

saveout

When the parameter 'saveout' is set to 'FALSE' (the default), a vector of calculated arse values are given for each case. When 'saveout' is set to 'TRUE', a dataframe of the original inputted dataset is returned with a new column of calculated arse values.

Value

When the parameter 'saveout' is set to 'FALSE', a vector of calculated arse values are given for each case. When 'saveout' is set to 'TRUE', a dataframe of the original inputted dataset is returned with a new column of calculated arse values.

Examples

xc <- t(c(1,2,3,4,5,6,7,8,9,10))
yc <- t(c(75,53,37,25,27,35,50,75,75,75))
dataset1 <- data.frame(xc, yc)
arse(data = dataset1, xcoord = dataset1[,1:10], ycoord = dataset1[,11:20], saveout = TRUE)