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Modified Index of Agreement (d1).

Source: R/reg_d1.R
d1.Rd

It estimates the modified index of agreement (d1) using absolute differences following Willmott et al. (1985).

Usage

d1(data = NULL, obs, pred, tidy = FALSE, na.rm = TRUE)

Arguments

data

(Optional) argument to call an existing data frame containing the data.

obs

Vector with observed values (numeric).

pred

Vector with predicted values (numeric).

tidy

Logical operator (TRUE/FALSE) to decide the type of return. TRUE returns a data.frame, FALSE returns a list; Default : FALSE.

na.rm

Logic argument to remove rows with missing values (NA). Default is na.rm = TRUE.

Value

an object of class numeric within a list (if tidy = FALSE) or within a data frame (if tidy = TRUE).

Details

Similar to d, the d1 index it is a normalized, dimensionless metric that tests general agreement. The difference with d, is that d1 uses absolute residuals instead of squared residuals. It is bounded between 0 and 1. The disadvantage is that d is an asymmetric index, that is, dependent to the orientation of predicted and observed values. For the formula and more details, see online-documentation

References

Willmott et al. (1985). Statistics for the evaluation and comparison of models. J. Geophys. Res. 90, 8995. doi:10.1029/jc090ic05p08995

Examples

# \donttest{
set.seed(1)
X <- rnorm(n = 100, mean = 0, sd = 10)
Y <- rnorm(n = 100, mean = 0, sd = 9)
d1(obs = X, pred = Y)
#> $d1
#> [1] 0.305442
#> 
# }