calculateWeightsPLS {cSEM}

Calculate composite weights using PLS-PM

Description

Calculate composite weights using the partial least squares path modeling (PLS-PM) algorithm (Wold 1975).

Usage

calculateWeightsPLS(
  .data                        = args_default()$.data,
  .S                           = args_default()$.S,
  .csem_model                  = args_default()$.csem_model,
  .conv_criterion              = args_default()$.conv_criterion,
  .iter_max                    = args_default()$.iter_max,
  .PLS_ignore_structural_model = args_default()$.PLS_ignore_structural_model,
  .PLS_modes                   = args_default()$.PLS_modes,
  .PLS_weight_scheme_inner     = args_default()$.PLS_weight_scheme_inner,
  .starting_values             = args_default()$.starting_values,
  .tolerance                   = args_default()$.tolerance
   )

Arguments

.data

A data.frame or a matrix of standardized or unstandardized data (indicators/items/manifest variables). Possible column types or classes of the data provided are: "logical", "numeric" ("double" or "integer"), "factor" ("ordered" and/or "unordered"), "character" (converted to factor), or a mix of several types.

.S

The (K x K) empirical indicator correlation matrix.

.csem_model

A (possibly incomplete) cSEMModel-list.

.conv_criterion

Character string. The criterion to use for the convergence check. One of: "diff_absolute", "diff_squared", or "diff_relative". Defaults to "diff_absolute".

.iter_max

Integer. The maximum number of iterations allowed. If iter_max = 1 and .approach_weights = "PLS-PM" one-step weights are returned. If the algorithm exceeds the specified number, weights of iteration step .iter_max - 1 will be returned with a warning. Defaults to 100.

.PLS_ignore_structural_model

Logical. Should the structural model be ignored when calculating the inner weights of the PLS-PM algorithm? Defaults to FALSE. Ignored if .approach_weights is not PLS-PM.

.PLS_modes

Either a named list specifying the mode that should be used for each construct in the form "construct_name" = mode, a single character string giving the mode that should be used for all constructs, or NULL. Possible choices for mode are: "modeA", "modeB", "modeBNNLS", "unit", "PCA", a single integer or a vector of fixed weights of the same length as there are indicators for the construct given by "construct_name". If only a single number is provided this is identical to using unit weights, as weights are rescaled such that the related composite has unit variance. Defaults to NULL. If NULL the appropriate mode according to the type of construct used is chosen. Ignored if .approach_weight is not PLS-PM.

.PLS_weight_scheme_inner

Character string. The inner weighting scheme used by PLS-PM. One of: "centroid", "factorial", or "path". Defaults to "path". Ignored if .approach_weight is not PLS-PM.

.starting_values

A named list of vectors where the list names are the construct names whose indicator weights the user wishes to set. The vectors must be named vectors of "indicator_name" = value pairs, where value is the (scaled or unscaled) starting weight. Defaults to NULL.

.tolerance

Double. The tolerance criterion for convergence. Defaults to 1e-05.

Value

A named list. J stands for the number of constructs and K for the number of indicators.

⁠$W⁠

A (J x K) matrix of estimated weights.

⁠$E⁠

A (J x J) matrix of inner weights.

⁠$Modes⁠

A named vector of modes used for the outer estimation.

⁠$Conv_status⁠

The convergence status. TRUE if the algorithm has converged and FALSE otherwise. If one-step weights are used via .iter_max = 1 or a non-iterative procedure was used, the convergence status is set to NULL.

⁠$Iterations⁠

The number of iterations required.

References

Wold H (1975). “Path models with latent variables: The NIPALS approach.” In Blalock HM, Aganbegian A, Borodkin FM, Boudon R, Capecchi V (eds.), Quantitative Sociology, International Perspectives on Mathematical and Statistical Modeling, 307–357. Academic Press, New York.