modSel: Model selection on a list of 'unmarked' model fits

In unmarked: Models for Data from Unmarked Animals

Model selection on a list of unmarked model fits

Description

Model selection results from an unmarkedFitList

Arguments

object	an object of class "unmarkedFitList" created by the function fitList.
nullmod	optional character naming which model in the fitList contains results from the null model. Only used in calculation of Nagelkerke's R-squared index.

Value

An object of class unmarkedModSel.

Note

Two requirements exist to conduct AIC-based model-selection and model-averaging in unmarked. First, the data objects (ie, unmarkedFrames) must be identical among fitted models. Second, the response matrix must be identical among fitted models after missing values have been removed. This means that if a response value was removed in one model due to missingness, it needs to be removed from all models.

Author(s)

Richard Chandler [e-mail]

References

Nagelkerke, N.J.D. (2004) A Note on a General Definition of the Coefficient of Determination. Biometrika 78, pp. 691-692.

See Also

unmarkedModSel-class

Examples

data(linetran)
(dbreaksLine <- c(0, 5, 10, 15, 20)) 
lengths <- linetran$Length * 1000

ltUMF <- with(linetran, {
	unmarkedFrameDS(y = cbind(dc1, dc2, dc3, dc4), 
	siteCovs = data.frame(Length, area, habitat), dist.breaks = dbreaksLine,
	tlength = lengths, survey = "line", unitsIn = "m")
	})

fm1 <- distsamp(~ 1 ~1, ltUMF)
fm2 <- distsamp(~ area ~1, ltUMF)
fm3 <- distsamp( ~ 1 ~area, ltUMF)

fl <- fitList(Null=fm1, A.=fm2, .A=fm3)
fl

ms <- modSel(fl, nullmod="Null")
ms

coef(ms)                            # Estimates only
SE(ms)                              # Standard errors only
(toExport <- as(ms, "data.frame"))  # Everything

unmarked documentation built on April 3, 2025, 5:30 p.m.