get.xblocks.any {ThurMod}

Get extra blocks in a Thurstonian design, that links as few blocks as possible.

Description

The function creates extra blocks in a Thurstonian design, that links as few initial blocks as possible, with the number of blocks determined by 'count.xblocks'. This is only useful for comparisons between linked and partially linked block designs (Jansen & Schulze, 2023).

Usage

get.xblocks.any(blocks, itf, multidim)

Arguments

blocks

A matrix defining the blocks of the model. The number of rows must be the number of blocks, each row represents a block and contains the item numbers. The number of columns present the number of items per block.

itf

A vector defining the items-to-factor relation. For example 'c(1,1,1,2,2,2)' defines six items, the first three correspond to factor 1, the second three correspond to factor 2.

multidim

Logical. Should the items within each linking block be forced to be multidimensional?

Details

The main strategy of the function is to create extra blocks that link as few blocks as possible, with the number of blocks determined by 'count.xblocks'. Therefore, first all combinations of additional blocks with the first two blocks are created. If more extra blocks are needed the function uses block three, four, etc..

Value

The result is a matrix where the rows correspond to the specific extra blocks.

References

Jansen, M. T., & Schulze, R. (2023). The Thurstonian linked block design: Improving Thurstonian modeling for paired comparison and ranking data. Manuscript submitted.

Examples

# Define a matrix of blocks
blocks <- matrix(1:15,ncol=3, byrow=TRUE)

# define the item-to-factor relation
itf <- rep(1:3,5)

# Get the extra blocks for a partially linked design
get.xblocks.any(blocks, itf, FALSE)