Description Usage Arguments Details Value Author(s) References See Also Examples

View source: R/Custom.functions.R

This function creates a model selection table from model input (log-likelihood, number of estimated parameters) supplied by the user instead of extracting the values automatically from a list of candidate models. The models are ranked based on one of the following information criteria: AIC, AICc, QAIC, QAICc. The table ranks the models based on the selected information criteria and also provides delta AIC and Akaike weights.

1 2 |

`logL` |
a vector of log-likelihood values for the models in the candidate model set. |

`K` |
a vector containing the number of estimated parameters for each model in the candidate model set. |

`modnames` |
a character vector of model names to facilitate the identification of
each model in the model selection table. If |

`second.ord` |
logical. If |

`nobs` |
the sample size required to compute the AICc or QAICc. |

`sort` |
logical. If |

`c.hat` |
value of overdispersion parameter (i.e., variance inflation factor)
such as that obtained from |

`aictabCustom`

constructs a model selection table based on one of
the four information criteria: AIC, AICc, QAIC, and QAICc. This
function is most useful when model input is imported into R from other
software (e.g., Program MARK, PRESENCE) or for model classes that are
not yet supported by `aictab`

.

`aictabCustom`

creates an object of class `aictab`

with the
following components:

`Modname` |
the names of each model of the candidate model set. |

`K ` |
the number of estimated parameters for each model. |

`(Q)AIC(c) ` |
the information criteria requested for each model (AICc, AICc, QAIC, QAICc). |

`Delta_(Q)AIC(c) ` |
the appropriate delta AIC component depending on the information criteria selected. |

`ModelLik ` |
the relative likelihood of the model given the data (exp(-0.5*delta[i])). This is not to be confused with the likelihood of the parameters given the data. The relative likelihood can then be normalized across all models to get the model probabilities. |

`(Q)AIC(c)Wt` |
the Akaike weights, also termed "model probabilities" sensu Burnham and Anderson (2002) and Anderson (2008). These measures indicate the level of support (i.e., weight of evidence) in favor of any given model being the most parsimonious among the candidate model set. |

`Cum.Wt ` |
the cumulative Akaike weights. These are only meaningful if results in table are sorted in decreasing order of Akaike weights (i.e., sort = TRUE). |

`c.hat` |
if c.hat was specified as an argument, it is included in the table. |

`LL` |
if c.hat = 1 and parameters estimated by maximum likelihood, the log-likelihood of each model. |

`Quasi.LL` |
if c.hat > 1, the quasi log-likelihood of each model. |

Marc J. Mazerolle

Anderson, D. R. (2008) *Model-based Inference in the Life Sciences:
a primer on evidence*. Springer: New York.

Burnham, K. P., Anderson, D. R. (2002) *Model Selection and
Multimodel Inference: a practical information-theoretic
approach*. Second edition. Springer: New York.

Dail, D., Madsen, L. (2011) Models for estimating abundance from
repeated counts of an open population. *Biometrics* **67**,
577–587.

Lebreton, J.-D., Burnham, K. P., Clobert, J., Anderson, D. R. (1992)
Modeling survival and testing biological hypotheses using marked
animals: a unified approach with case-studies. *Ecological
Monographs* **62**, 67–118.

MacKenzie, D. I., Nichols, J. D., Lachman, G. B., Droege, S., Royle,
J. A., Langtimm, C. A. (2002) Estimating site occupancy rates when
detection probabilities are less than one. *Ecology* **83**,
2248–2255.

MacKenzie, D. I., Nichols, J. D., Hines, J. E., Knutson, M. G.,
Franklin, A. B. (2003) Estimating site occupancy, colonization, and
local extinction when a species is detected imperfectly. *Ecology*
**84**, 2200–2207.

Mazerolle, M. J. (2006) Improving data analysis in herpetology: using
Akaike's Information Criterion (AIC) to assess the strength of
biological hypotheses. *Amphibia-Reptilia* **27**, 169–180.

Royle, J. A. (2004) *N*-mixture models for estimating population
size from spatially replicated counts. *Biometrics* **60**,
108–115.

`AICcCustom`

, `confset`

, `c_hat`

,
`evidence`

, `modavgCustom`

1 2 3 4 5 6 7 8 9 10 11 12 | ```
##vector with model LL's
LL <- c(-38.8876, -35.1783, -64.8970)
##vector with number of parameters
Ks <- c(7, 9, 4)
##create a vector of names to trace back models in set
Modnames <- c("Cm1", "Cm2", "Cm3")
##generate AICc table
aictabCustom(logL = LL, K = Ks, modnames = Modnames, nobs = 121,
sort = TRUE)
``` |

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