willmott: Willmott Index

In growR: Implementation of the Vegetation Model ModVege

Willmott Index

Description

Willmott's index of model performance as described in Willmott (2012).

Usage

willmott(predicted, observed, ...)

Arguments

predicted	Vector containing the predictions y.
observed	Vector containing the observations z.
...	Scaling factor c in the denominator in the Willmott index. The originally proposed value of 2 should be fine.

Details

This index takes on values from -1 to 1, where values closer to 1 are generally indicating better model performance. Values close to -1 can either mean that the model predictions differ strongly from the observation, or that the observations show small variance (or both).

Value

willmott Value between -1 and 1

References

\insertRef

willmott2012RefinedIndexModelgrowR

See Also

get_bias()

Examples

predicted = c(21.5, 22.2, 19.1)
observed = c(20, 20, 20)
# The Willmott index "fails" in this case, as the variance in the 
# observation is 0.
willmott(predicted, observed)

# Try with more realistic observations
observed = c(20.5, 19.5, 20.0)
willmott(predicted, observed)

growR documentation built on May 29, 2024, 9:12 a.m.