visit (version 2.2)

vtDecMap: Obtain decision map information

Description

Summarize the posterior distribution of \(\theta^{(l)}_{00}, \theta^{(l)}_{01}, \theta^{(l)}_{10}, \theta^{(l)}_{11}\) and get information for making dose escalation decisions

Usage

vtDecMap(thetas, etas, prev.res = 0, dec.cut = 0.6)

Value

A class VTDEC list. See the return value from vtInterim

for details.

Arguments

thetas

Posterior samples of \(\theta\), a class VTPOST matrix generated by vtPost

etas

Vector of length 2 representing \((p_L, p_U)\). \(p_L\): lower bound of DLT risk, below which the current dose is considered absolutely safe; \(p_U\): upper bound of DLT risk above which the current dose is considered too toxic

prev.res

Response rate from the next lower dose level, say, \(l-1\). This can be a scalar representing the mean of the response rate \(E(q^{(l-1)})\), or a vector of posterior samples of the response rate \(q^{(l-1)}\). For \(l=1\), this value is set to \(0\).

dec.cut

Thresholds \(C_1,C_2,C_3\). If the vector length is shorter than \(3\), it is repeated to have \(3\) elements. See visit for details.

Details

This function summarizes the posterior distribution of the \(\theta^{(l)}_{00}, \theta^{(l)}_{01}, \theta^{(l)}_{10}, \theta^{(l)}_{11}\) and sequentially get the conditional probabilities of each decision map region. See visit for details of the decision map regions.

Examples

etas     <- c(0.1, 0.3)
dec.cut  <- c(0.6,0.6,0.6)
obs.y    <- rbind(c(5, 2, 0, 0))
rst.post <- vtPost(obs.y,  prob.mdl = "NONPARA", nsmp = 2000)
dec.map  <- vtDecMap(rst.post, etas = etas, dec.cut = dec.cut)