In markheckmann/OpenRepGrid: Tools to Analyze Repertory Grid Data

knitr::opts_chunk$set(collapse = TRUE, comment = "#")
options(width=120)
library(OpenRepGrid)
settings(show.scale=FALSE, show.meta=FALSE, show.cut=30)

Description

The direction of the constructs in a grid is arbitrary and a reflection of a scale does not affect the information contained in the grid. Nonetheless, the direction of a scale has an effect on inter-element correlations [@mackay_identification_1992] and on the spatial representation and clustering of the grid [@bell_note_2010]. Hence, it is desirable to follow a protocol to align constructs that will render unique results. A common approach is to align constructs by pole preference, i.e. aligning all positive and negative poles. This can e. g. be achieved using the function swapPoles. If an ideal element is present the function alignByIdeal will align the constructs accordingly. Note that this approach does not always yield definite results as sometimes ratings do not show a clear preference for one pole [@winter_midpoint_2010]. If a preference cannot be determined definitely, the construct direction remains unchanged (a warning is issued in that case).

@bell_note_2010 proposed another solution for the problem of construct alignment. As a unique protocol he suggests to align constructs in a way so they all have positive loadings on the first component of a grid PCA.

R-Code

Align by ideal/preference

To align a construct by preference, an ideal element has to be defined. For the following example it is element 13 (ideal self).

alignByIdeal(feixas2004, 13) 

Note that when midpoint ratings are present no preferred pole can be identified, as it is the case for one construct in the example above.

As a default the preferred poles are assigned to the right side. You can use the argument high=FALSE to indicate that high ratings will correspond to the negative pole. Hence, the preferred pole will be in the left side of the grid.

alignByIdeal(feixas2004, 13, high=F) 

To save the assigned grid into a new object:

x <- alignByIdeal(feixas2004, 13) 

Align by loadings

The alignment operation using OpenRepGrid is performed by the function alignByLoadings.

alignByLoadings(bell2010)

To save the alignment information in an object:

x <- alignByLoadings(bell2010)

To get more information about the function type: ?alignByLoadings to the console to open the help menu for the function. As a default the function will return a list containing:

Name of list element | Content ----- | ------- cor.before | Construct correlation matrix before reversal loadings.before | Loadings on PCs before reversal reversed | Constructs that have been reversed cor.after | Construct correlation matrix after reversal loadings.after | Loadings on PCs after reversal

names(x)

To extract the indices that need reversal and use them to swap the poles you may do:

swapPoles(bell2010, x$reversed$index)

This is clumsy though and will be subject to change in later versions of OpenRepGrid.

Literature

markheckmann/OpenRepGrid documentation built on April 14, 2024, 8:15 a.m.