overlap: Multiple scaling - the overlapping way
In elisr: Exploratory Likert Scaling

Description Usage Arguments Details Value References Examples

View source: R/overlap.R

overlap() returns a overlapped version (either extended, or reversed, or both) of the specified msdf.

overlap(
  msdf,
  mrit_min = NULL,
  negative_too = FALSE,
  overlap_with = "fragment",
  sclvals = NULL,
  use = "pairwise.complete.obs"
)

`msdf`	a multiple scaled data frame (built with `disjoint()`).
`mrit_min`	a numeric constant of length 1 to specify the marginal corrected item-total correlation. Its value is in the range of 0-1. The default is set to `.3`.
`negative_too`	a logical constant indicating whether reversed items are included in the analysis. The default is set to `FALSE`.
`overlap_with`	a string telling `overlap()` the set of items for the extension. To build up on all variables of a fragment use `fragment`, for the core-only option type `core`. The default is set to "fragment".
`sclvals`	a numeric vector of length 2 indicating the start- and endpoint of a scale. Use something like `c(min,max)`.
`use`	an optional string to specify how missing values enter the analysis. See `use` in `cor` for details. The default is set to `pairwise.complete.obs`.

use clarifies how to set up a correlation matrix in the presence of missing values. In a typical scaling process this happens at least twice. First, when determining the core items (the two items in the correlation matrix with the highest linear relationship). Second, when an item is proposed for an emerging scale.

Note that overlap() uses cor's default method pearson.

A multiple scaled data frame (msdf).

Müller-Schneider, T. (2001). Multiple Skalierung nach dem Kristallisationsprinzip / Multiple Scaling According to the Principle of Crystallization. Zeitschrift für Soziologie, 30(4), 305-315. https://doi.org/10.1515/zfsoz-2001-0404

# Build a msdf
msdf <- disjoint(mtcars, mrit_min = .4)

# Use positive correlations (extend on fragments)
overlap(msdf, mrit_min = .6)

# Use positive correlations (extend on cores)
overlap(msdf, mrit_min = .6, overlap_with = "core")

# Include negative correlations
overlap(msdf, mrit_min = .7, negative_too = TRUE, sclvals = c(-3,3))

# Change the treatment of missing values
overlap(msdf, mrit_min = .6, use = "all.obs")