plspm.formula (version 1.0.1)

plspm.params: Formula Based PLS Path Modeling Parameters Calculus

Description

This fonction compute the inner matrix and the outer list need for specify the PLS Path Models in the package 'plspm' (function 'plspm'). The parameters are compute using a formula specification of the PLSPM model.

Usage

plspm.params(Formula,Data)

Arguments

Formula

A string describe the the inner and outer model using formulas. The inner models are describe using "=~" and "~~" for the inner model. (see details)

Data

matrix or data frame containing the manifest variables.

Value

A list containing two objects :

inner.mat

inner matrix specify the structural relations between latents variables

outer.list

outer list specify the indexes of the manifests variables in the dataset for each latent variable

Details

The function 'plspm.formula' estimates a path model by partial least squares approach providing the full set of results as the plspm function of the 'plspm' package. The algorithm compute itself the path matrix and the blocks list. To do that, the model must be specify using the two rules below :

LatVar1 =~ ManVar1+ManVar2+ManVar3

Description of the relation between the latent variable (LatVar1) and its manifests variables (ManVar1, ManVar2 and ManVar3

LatVar3 ~~ LatVar1+LatVar2

Description of the relation between the latent variable (LatVar3) and the other latents variables (LatVar1 and ManVar2) linked to that variable

All the formulars must be in a single string with a newline as separator. Phisical new lines are generally used (see example).

Examples

# Load data (satisfaction data in plspm package)
data("plspmsat")
## Model specification by formulas 
satmodele <- "
            ## measure model specification
              EXPE =~ expe1+expe2+expe3+expe4+expe5
              IMAG =~ imag1+imag2+imag3+imag4+imag5
              LOY =~ loy1+loy2+loy3+loy4
              SAT =~ sat1+sat2+sat3+sat4
              VAL =~ val1+val2+val3+val4 
              QUAL =~ qual1+qual2+qual3+qual4+qual5 
            ## outer model specification 
              EXPE ~~ IMAG
              LOY ~~ IMAG+SAT
              SAT ~~ IMAG+EXPE+QUAL+VAL
              VAL ~~ EXPE+QUAL
              QUAL ~~ EXPE
          "
## computer the PLSPM parameters
sat.param <- plspm.params(Formula = satmodele, Data = plspmsat)
sat.param$inner.mat  ## inner matrix
sat.param$outer.list  ##  outer list