*! version 1.0 20 Aug 2020

Title

doptimal -- To find the D-optimal Design for Dose Ranging studies

Syntax

doptimal
[varlist]
[if]
[,
options]

Optional
theta(numlist) specifies the model parameters or the starting values for the optimization routine.

maxdose(#) specifies the highest possible dose.

mindose(#) specifies the lowest possible dose.

model(string) specifies which model to assume, these can be selected from linear, quad, emax or log4.

usedata specifies that the model parameters are estimated from the current dataset

Description

doptimal is a command that produces the D-optimal design within a dose ranging design. The command either
takes some data and estimates the model parameters or the user can specify the model parameter values. Then with the paramter estimates the command will find the number of design points or doses, usually including the minimum and maximum doses and then will find the weights or proportion of people who should be allocated to each dose.

Options

Main

theta(numlist) specifies the model parameters or the starting values for the optimization routine.

maxdose(#) specifies the highest possible dose.

mindose(#) specifies the lowest possible dose.

model(string) specifies which model to assume, these can be selected from linear, quad, emax or log4.

usedata specifies that the model parameters are estimated from the current dataset

Examples

For the Emax model and assuming the model parameters are 1, 30 and 0.2, find the D-optimal design
by the following command

doptimal, theta(1 30 0.2) model(emax) mindose(0) maxdose(1.5)

Stored results

Matrices

r(design) The design matrix

r(theta) The model parameters

Author

Prof Adrian Mander, Cardiff University.

Email mandera@cardiff.ac.uk

See Also

Related commands:

crm (if installed) ssc install crm (to install this command)

mtpi (if installed) ssc install mtpi (to install this command)

pipe (if installed) ssc install pipe (to install this command)