MConjoint (version 0.1)

mc.add.to.design: Add cards to a design

Description

Given a "good" design add some cards to get a new design

Usage

mc.add.to.design(all.possible, old.design, cards.to.add = 3, slack = 1,  tol = 0.2, max.trials = 100, max.good.designs=100)
mc.add.to.design.fast(all.possible, old.design, cards.to.add = 3, slack = 1, tol = 0.2)

Arguments

all.possible

all possible cards (can be all combinations of factors, or some can be removed)

old.design

An initial "good" design

cards.to.add

the number of cards to add

slack

How much the number of each factor can vary in a "good" design

tol

The largest cross correlation in a "good" design

max.trials

The maximum number of samples of extra.cards cards to look at.

max.good.designs

For any trial design, the maximum number of good designs to look for

Value

base.design

The original old.design

added

The sample of cards added

design

The combined set of cards randomized

Details

The function will take samples of size extra.cards from the set of cards all.possible-old.design and add them to old.design. For each sample the number of "good" (balanced an low cross correlation) designs of the same size as old.design is found. The sample which gives the largest number of "good" designs is used.

The default max.trials of 100 will lead to run times of several hours for largish problems. You can usually decrease this without losing too much. Increasing the number of trials may increase the number of good designs found, but usually not by much.

The default max.good.designs is set to 100. Analyzing more than this number of designs is unlikely to be needed outside of theoretical work.

mc.add.to.design.fast is useful for quick and dirty work

Examples

data(hire.candidates)
base.design = mc.get.one.design(hire.candidates, 9)

#use defaults, (except max.trials=10 for speed)

mc.add.to.design(hire.candidates,base.design, max.trials=10)

#add 4 cards, accepting cross corellations up to .35
#warning, this may take several minutes

#mc.add.to.design(hire.candidates,base.design,4,tol=.35)

# you can speed this up and in this case
# have almost as many good designs (53 vs.54)

#mc.add.to.design(hire.candidates,base.design,4,tol=.35,max.trials=10)