nomLORgee(formula, data, id = id, repeated = NULL,
bstart = NULL, LORstr = "time.exch", LORem = "3way", LORterm = NULL,
add = 0, homogeneous = TRUE, control = LORgee.control(),
ipfp.ctrl = ipfp.control(), IM = "solve")
formula
, id
and repeated
."independence"
, "time.exch"
, "RC"
or "fixed"
."3way"
) or independently at each level pair of repeated
("2way"
).LORstr="fixed"
.LORstr="time.exch"
or "RC"
.ipfp
."solve"
, "qr.solve"
or "cholesky"
."LORgee"
. This has components:terms
structure describing the marginal model.contrasts
used for the factors.id
variable.repeated
variable.ipfp
.add
.pvalue of the Null model
corresponds to the hypothesis $H_0: \beta_1=...=\beta_{J-1}=0$ based on the Wald test statistic.data
must be provided in case level or equivalently in `long' format. See details about the `long' format in the function reshape.
A term of the form offset(expression)
is allowed in the right hand side of formula
.
The default set for the response categories is ${1,\ldots,J}$, where $J>2$ is the maximum observed response category. If otherwise, the function recodes the observed response categories onto this set.
The $J$-th response category is treated as baseline.
The default set for the id
labels is ${1,\ldots,N}$, where $N$ is the sample size. If otherwise, the function recodes the given labels onto this set.
The argument repeated
can be ignored only when data
is written in such a way that the $t$-th observation in each cluster is recorded at the $t$-th measurement occasion. If this is not the case, then the user must provide repeated
. The suggested set for the levels of repeated
is ${1,\ldots,T}$, where $T$ is the number of observed levels. If otherwise, the function recodes the given levels onto this set.
The variables id
and repeated
do not need to be pre-sorted. Instead the function reshapes data
in an ascending order of id
and repeated
.
The fitted marginal baseline category logit model is
$$log \frac{Pr(Y_{it}=j |x_{it})}{Pr(Y_{it}=J |x_{it})}=\beta_{0j} +\beta^{'}_j x_{it}$$
where $Y_{it}$ is the $t$-th multinomial response for cluster $i$, $x_{it}$ is the associated covariates vector, $\beta_{0j}$ is the $j$-th response category specific intercept and $\beta_{j}$ is the $j$-th response category specific parameter vector.
The LORterm
argument must be an $L$ x $J^2$ matrix, where $L$ is the number of level pairs of repeated
. These are ordered as $(1,2), (1,3), ...,(1,T), (2,3),...,(T-1,T)$ and the rows of LORterm
are supposed to preserve this order. Each row is assumed to contain the vectorized form of a probability table that satisfies the desired local odds ratios structure.## See the interpretation in Touloumis (2011).
data(housing)
fitmod <- nomLORgee(y~factor(time)*sec,data=housing,id=id)
summary(fitmod)
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