get.xblocks {ThurMod}

Get extra blocks in a Thurstonian design, that links all blocks.

Description

The function creates extra blocks for a Thurstonian design, that links all initial blocks with as few extra blocks as possible. The number of extra blocks is determined by 'count.xblocks' (see Jansen & Schulze, 2023).

Usage

get.xblocks(blocks, itf, multidim, item_not = NULL, min = FALSE,
  show.warnings = FALSE)

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?

item_not

The items that are differently keyed compared to the majority of items.

min

Logical. Should a minimal number of blocks contain mixed keyed items?

show.warnings

Logical. Should warnings be shown?

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 completely linked design
get.xblocks(blocks, itf, FALSE)