# tmbroot: Compute likelihood profile confidence intervals of a TMB... In TMB: Template Model Builder: A General Random Effect Tool Inspired by 'ADMB'

 tmbroot R Documentation

## Compute likelihood profile confidence intervals of a TMB object by root-finding

### Description

Compute likelihood profile confidence intervals of a TMB object by root-finding in contrast to `tmbprofile`, which tries to compute somewhat equally spaced values along the likelihood profile (which is useful for visualizing the shape of the likelihood surface), and then (via `confint.tmbprofile`) extracting a critical value by linear interpolation,

### Usage

``````tmbroot(
obj,
name,
target = 0.5 * qchisq(0.95, df = 1),
lincomb,
parm.range = c(NA, NA),
sd.range = 7,
trace = FALSE,
continuation = FALSE
)
``````

### Arguments

 `obj` Object from `MakeADFun` that has been optimized. `name` Name or index of a parameter to profile. `target` desired deviation from minimum log-likelihood. Default is set to retrieve the 95 if the objective function is a negative log-likelihood function `lincomb` Optional linear combination of parameters to profile. By default a unit vector corresponding to `name`. `parm.range` lower and upper limits; if `NA`, a value will be guessed based on the parameter value and `sd.range` `sd.range` in the absence of explicit `parm.range` values, the range chosen will be the parameter value plus or minus `sd.range` times the corresponding standard deviation. May be specified as a two-element vector for different ranges below and above the parameter value. `trace` report information? `continuation` use continuation method, i.e. set starting parameters for non-focal parameters to solutions from previous fits?

### Value

a two-element numeric vector containing the lower and upper limits (or `NA` if the target is not achieved in the range), with an attribute giving the total number of function iterations used

### Examples

``````## Not run:
runExample("simple",thisR=TRUE)
logsd0.ci <- tmbroot(obj,"logsd0")

## End(Not run)
``````

TMB documentation built on Nov. 27, 2023, 5:12 p.m.