rev.capthist: Reverse Primary Sessions

In openCR: Open Population Capture-Recapture

Reverse Primary Sessions

Description

The rev method for capthist objects reverses the order of the primary sessions while retaining the order of secondary sessions within each primary session.

Usage

## S3 method for class 'capthist'
rev(x)

Arguments

x	multi-session capthist object from secr

Details

rev() is used to demonstrate 'reversed time' analyses (Nichols 2016) in which seniority (gamma) is estimated as reversed-time survival (phi) The approach is numerically equivalent to direct modelling of seniority (see Examples). Direct modelling allows more control and is more intuitive.

If x is not overtly multi-session and has no intervals attribute then each occasion is treated as a primary session.

Value

Capthist object with same observations as input, but re-ordered. The order of attributes sessionlabels and intervals is also reversed. A default intervals attribute is added if the input lacks one.

References

Nichols, J. D. (2016) And the first one now will later be last: time-reversal in Cormack–Jolly–Seber Models. Statistical Science 31, 175–190.

Examples

summary(rev(ovenCH), terse = TRUE)

# These three models give the same result for gamma except for
# gamma(1982) which is confounded with p and not separately estimable:

## Not run: 

dipperPradel <- openCR.fit(dipperCH, type = "Pradelg", model = list(p~t, phi~t, gamma~t))
revdipper <- openCR.fit(rev(dipperCH), model=list(p~t, phi~t))
dipperJSSA <- openCR.fit(dipperCH, type='JSSAgCL', model=list(p~t, phi~t, gamma~t))

predict(dipperPradel)$gamma
predict(revdipper)$phi
predict(dipperJSSA)$gamma


## End(Not run)

openCR documentation built on Sept. 25, 2022, 5:06 p.m.