# d: Willmott's Index of Agreement (d) In metrica: Prediction Performance Metrics

 d R Documentation

## Willmott's Index of Agreement (d)

### Description

It estimates the Willmott's index of agreement (d) for a continuous predicted-observed dataset.

### Usage

``````d(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.

### Details

The d index it is a normalized, dimensionless metric that tests general agreement. It measures both accuracy and precision using squared residuals. It is bounded between 0 and 1. The disadvantage is that d is an asymmetric index, that is, dependent to what is orientation of predicted and observed values. For the formula and more details, see online-documentation

### Value

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

### References

Willmott (1981). On the validation of models. Phys. Geogr. 2, 184–194. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.1080/02723646.1981.10642213")}

### Examples

``````
set.seed(1)
X <- rnorm(n = 100, mean = 0, sd = 10)
Y <- rnorm(n = 100, mean = 0, sd = 9)
d(obs = X, pred = Y)

``````

metrica documentation built on June 30, 2024, 5:07 p.m.