SEMinR brings many advancements to creating and estimating structural equation models (SEM) using Partial Least Squares Path Modeling (PLS-PM):

• A natural feeling, domain-specific language to build and estimate structural equation models in R
• Uses variance-based PLS estimation to model both composite and common-factor constructs
• High-level functions to quickly specify interactions and complicated structural models

SEMinR follows the latest best-practices in methodological literature:

• Automatically adjusts PLS estimates to ensure consistency (PLSc) wherever common factors are involved
• Ajusts for known biases in interaction terms in PLS models
• Continuously tested against leading PLSPM software to ensure parity of outcomes: SmartPLS (Ringle et al., 2015) and ADANCO (Henseler and Dijkstra, 2015), as well as other R packages such as semPLS (Monecke and Leisch, 2012) and matrixpls (Rönkkö, 2016)
• High performance, multi-core bootstrapping function

Documentation

The vignette for Seminr can be found in the CRAN folder or by running the vignette("SEMinR") command after installation.

Demo code for use of Seminr can be found in the seminr/demo/ folder or by running the demo("seminr-contained"), demo("seminr-ecsi") or demo("seminr-interaction") commands after installation.

Installation

You can install SEMinR with:

install.packages("seminr")

Usage

Briefly, there are four steps to specifying and estimating a structural equation model using SEMinR:

1 Describe measurement model for each construct and its items including any interactions or higher order constructs:

# Distinguish and mix composite or reflective (common-factor) measurement models
measurements <- constructs(
  composite("Image",       multi_items("IMAG", 1:5), weights = mode_B),
  composite("Expectation", multi_items("CUEX", 1:3), weights = mode_A),
  reflective("Loyalty",    multi_items("CUSL", 1:3)),
  composite("Quality",      multi_items("PERQ", 1:7)),
  composite("Complaints",   single_item("CUSCO")),
  interaction_term(iv = "Image", moderator = "Expectation", method = orthogonal),
  interaction_term(iv = "Image", moderator = "Value", method = orthogonal),
  higher_composite("Value", dimensions = c("Quality","Complaints"), method = two_stage, weights = mode_B)
)

2 Describe the structural model of causal relationships between constructs (and interactions):

# Quickly create multiple paths "from" and "to" sets of constructs
structure <- relationships(
  paths(from = c("Image", "Expectation", "Image*Expectation","Image*Value"), 
        to = "Loyalty")
)

3 Put the above elements together to estimate and bootstrap the model:

# Dynamically compose SEM models from individual parts
pls_model <- estimate_pls(data = mobi, measurements, structure)
summary(pls_model)

# Use multi-core parallel processing to speed up bootstraps
boot_estimates <- bootstrap_model(pls_model, nboot = 1000, cores = 2)
summary(boot_estimates)

Authors

• Soumya Ray
• Nicholas Danks