balanced.pcdesign function

Balanced Paired-Comparison Design

Creates a (completely) balanced paired-comparison design.

balanced.pcdesign(nstimuli)

Arguments

• nstimuli: number of stimuli in the paired-comparison design

Details

When nstimuli is odd, the presentation order is completely balanced, that is any given stimulus appears an equal number of times as the first and second member of a pair. When nstimuli is even, the presentation order is balanced as much as possible. Subjects should be equally assigned to listA and listB for the purpose of balancing the within-pair presentation order across a sample of subjects. Pairs should be re-randomized for each subject. See David (1988) for details.

Returns

• pairs: a character array holding the balanced pairs

• listA: the vector pairs in the original within-pair order

• listB: the vector of pairs in the inverted within-pair order

References

David, H. (1988). The method of paired comparisons. London: Griffin.

See Also

pcX, eba.

Examples

## Create balanced design for 6 stimuli
bp <- balanced.pcdesign(6)

## Replicate each within-pair order 10 times and re-randomize
cbind(replicate(10, sample(bp$listA)), replicate(10, sample(bp$listB)))