computeImbalances: A function to compute imbalances resulting from assigning...
In SRS: Subject Randomization System

Description Usage Arguments Value Author(s) References See Also Examples

This function computes the imbalances resulting from assigning each of the treatments in turn for a prospective subject coming in with the factors specified

1	computeImbalances(object, factor.values)

`object`	An object of class `PocockSimonRandomizer`
`factor.values`	A vector of character values specifying the level of each factor

The result is an m by n matrix of values, where m is the number of factors and n is the number of treatments. The entries are what the counts of subjects assigned to each treatment would be for the levels of the factors specified. Suppose the factor levels are first level of factor 1, F1:1, third level of factor 2, F2:3, and second level of factor 3, F3:2 and there are four treatments Tr1, Tr2, Tr3, and Tr4. Then the 3 by 4 matrix has row names F1-1, F2-3, F3-2 and column names Tr1, Tr2, Tr3, Tr4. The first row would indicate the range of imbalance of subject counts (assuming default imbalance function of range) for each of the four treatments.

Balasubramanian Narasimhan

Sequential Treatment Assigment with Balancing for Prognostic Factors in the Controlled Clinical Trial, by S.~J.~Pocock and R.~Simon, Biometrics, 31, 103-115

computeOverallImbalance

expt <- ClinicalExperiment(number.of.factors = 3,
                           number.of.factor.levels = c(2, 2, 3),
                           number.of.treatments = 3)
r.obj <- new("PocockSimonRandomizer", expt, as.integer(12345))
computeImbalances(r.obj, c("1","2","2"))
##
## Another example
##
ex.matrix <- matrix (c(9,8,8,9,8,4,5,
                       10,7,6,11,8,5,4,
                       9,7,7,9,8,3,5), nrow=3, byrow=TRUE)

rownames(ex.matrix) <- c("Tr1", "Tr2", "Tr3")
colnames(ex.matrix) <- c("F1:1", "F1:2", "F2:1", "F2:2", "F3:1", "F3:2", "F3:3")
stateTable(r.obj) <- ex.matrix
computeImbalances(r.obj, c("1","2","2"))