getprior {dfcrm} | R Documentation |
Returns a vector of initial guesses of toxicity probabilities associated the doses for a given model sensitivity (set of indifference intervals).
getprior(halfwidth, target, nu, nlevel, model = "empiric", intcpt = 3)
halfwidth |
The desired halfwidth of the indifference intervals. |
target |
The target DLT rate. |
nu |
The prior guess of MTD. |
nlevel |
The number of test doses. |
model |
A character string to specify the working model used in the method. The default model is ``empiric''. A one-parameter logistic model is specified by ``logistic''. |
intcpt |
The intercept of the working logistic model. The
default is 3. If model =``empiric'', this argument will be
ignored. |
getprior
is an ``inverse'' function of crmsens
which
gives the indifference intervals for a given set of initial guesses.
A vector of length nlevel
is returned.
Cheung, Y. K. and Chappell, R. (2002). A simple technique to evaluate model sensitivity in the continual reassessment method. Biometrics 58:671-674.
target <- 0.25 delta <- 0.10 mtd0 <- 3 # initial DLT rates with indifference intervals [0.15, 0.35]. prior <- getprior(delta, target, mtd0,nlevel=6, model="logistic")