# varEst: Estimate the Frailty Variance for Discrete-Time Multivariate... In lclGWAS: Efficient Estimation of Discrete-Time Multivariate Frailty Model Using Exact Likelihood Function for Grouped Survival Data

## Description

A method to estimate the frailty variance for a multivariate frailty model accounting for family structure of related individuals (i.e., trios). The input data is assumed to be organized such that records for each family occur consecutively, and that records for offspring precede those for parents. The variance matrix for the random effects is assumed to be of the form `var`*K, where K is a matrix of kinship coefficients between family members. The following groupings are permitted: (Individual), (Offspring, Offspring), (Offspring, Parent), (Offspring, Parent, Parent), and (Offspring, Offspring, Parent, Parent). Other family structures have not been implemented.

## Usage

 `1` ``` varEst(fam_group, alpha, dtime, delta, g, beta, lower, upper) ```

## Arguments

 `fam_group` Vector of family indicators for each sample. `alpha` Vector of baseline survival rates for each time interval. `dtime` Vector of observed discrete survival times for each sample. `delta` Event indicator vector: 1 indicates observed event, 0 indicates censored. `g` Vector of numeric genotypes for each sample. `beta` Scalar for the fixed effect size. `lower` Scalar for the lower bound of the variance estimation search region. `upper` Scalar for the upper bound of the variance estimation search region.

## Value

A `list` with one object:

 `varEst` Scalar estimate of the frailty variance.

## Examples

 ```1 2 3 4 5 6 7 8 9``` ```# Generate dummy data fam_group <- rep(1:3,each=3) alpha <- c(0.7500000, 0.6666667, 0.5000000, 0.0000000) dtime <- c(1, 3, 3, 2, 1, 1, 2, 3, 1) delta <- c(1, 0, 1, 1, 1, 0, 1, 0, 1) g <- c(0, 1, 1, 1, 2, 2, 0, 0, 0) beta <- 1 res <- varEst(fam_group, alpha, dtime, delta, g, beta, lower = 0, upper = 2) res ```

lclGWAS documentation built on May 2, 2019, 2:46 p.m.