addinteger function

Add an Integer Penalty to an Existing Distance Matrix

Takes an integer valued covariate, and adds a penalty proportional to the difference in the integer values, with proportionality constant penalty.

addinteger(costmatrix, z, iscore, penalty = 1000)

Arguments

• costmatrix: An existing cost matrix with sum(z) rows and sum(1-z) columns. The function checks the compatability of costmatrix, z and p; so, it may stop with an error if these are not of appropriate dimensions. In particular, costmatrix may come from startcost().
• z: A vector with z[i]=1 if individual i is treated or z[i]=0 if individual i is control. The rows of costmatrix refer to treated individuals and the columns refer to controls.
• iscore: An vector of integers with length equal to length(z).
• penalty: One positive number used to penalize mismatches for iscore.

Details

If a treated and control individual differ on iscore in absolute value by dif, then the distance between them is increased by adding dif*penalty.

Returns

A penalized distance matrix.

Author(s)

Paul R. Rosenbaum

Examples

data(binge)
# Select two treated and four controls from binge
d<-binge[is.element(binge$SEQN,c(109315,109365,109266,109273,109290,109332)),]
attach(d)
z<-1*(AlcGroup=="B")
names(z)<-d$SEQN
rbind(z,education)
dist<-startcost(z)
addinteger(dist,z,education,penalty=3)
detach(d)
rm(d,dist,z)