VT.tree-abstract: Tree to find subgroup

In aVirtualTwins: Adaptation of Virtual Twins Method from Jared Foster

Description

An abstract reference class to compute tree

Details

VT.tree.class and VT.tree.reg are children of VT.tree. VT.tree.class and VT.tree.reg try to find a strong association between difft (in VT.difft object) and RCT variables.

In VT.tree.reg, a regression tree is computed on difft values. Then, thanks to the threshold it flags leafs of the tree which are above the threshold (when sens is ">"). Or it flags leafs which are below the threshold (when sens = "<").

In VT.tree.class, it first flags difft above or below (depending on the sens) the given threshold. Then a classification tree is computed to find which variables explain flagged difft.

To sum up, VT.tree try to understand which variables are associated with a big change of difft.

Results are shown with getRules() function. only.leaf parameter allows to obtain only the leaf of the tree. only.fav parameter select only favorable nodes. tables shows incidence table of the rule. verbose allow getRules() to be quiet. And compete show also rules with maxcompete competitors from the tree.

Fields

vt.difft

VT.difft object

outcome

outcome vector from rpart function

threshold

numeric Threshold for difft calculation (c)

screening

Logical. TRUE if using varimp. Default is VT.object screening field

sens

character Sens can be ">" (default) or "<". Meaning : difft > threshold or difft < threshold

name

character Names of the tree

tree

rpart Rpart object to construct the tree

Ahat

vector Indicator of beglonging to Ahat

Methods

computeNameOfTree(type)

return label of response variable of the tree

createCompetitors()

Create competitors table

getAhatIncidence()

Return Ahat incidence

getAhatQuality()

Return Ahat quality

getData()

Return data used for tree computation

getIncidences(rule, rr.snd = T)

Return incidence of the rule

getInfos()

Return infos about tree

getRules(only.leaf = F, only.fav = F, tables = T, verbose = T, compete = F)

Return subgroups discovered by the tree. See details.

run(...)

Compute tree with rpart parameters

See Also

VT.tree.reg, VT.tree.class

aVirtualTwins documentation built on May 2, 2019, 4:04 p.m.