README

This package includes functions for forming the likelihood-based confidence intervals (LBCIs) for parameters in structural equation modeling. It also supports the robust LBCI proposed by Falk (2018). It was described in the following manuscript:

As argued in the article and by others, LBCI is usually better than Wald-based confidence interval and delta method confidence interval, which are the default method in most structural equation modeling (SEM) program. However, there is one technical disadvantage: LBCI cannot be directly computed but needs to be “found” (searched) by some algorithms. Wald CIs, on the other hand, can be computed quickly.

In semlbci, we try to address this disadvantage of LBCI by implementing an efficient method (illustrated by Pek & Wu, 2018, adapted from Wu & Neale, 2012), to help researchers to form LBCIs for model parameters, including user-defined parameters, in models fitted by lavaan. It can also form LBCIs for the standardized solution, such as “betas” (standardized regression coefficients) and correlations, and support multiple-group models. Last, it supports the robust LBCI proposed by Falk (2018) for nonnormal variables.

How To Use It

Illustration with examples can be found in the Get Started guide (vignette("semlbci", package = "semlbci")).

Installation

install.packages("semlbci")

remotes::install_github("sfcheung/semlbci")

Implementation

It currently implements the algorithm illustrated by Pek and Wu (2018), adapted from Wu and Neale (2012) without adjustment for parameters with attainable bounds. It also supports the robust LBCI proposed by Falk (2018). More on the implementation can be found in the technical appendices.

References

Cheung, S. F., & Pesigan, I. J. A. (2023). semlbci: An R package for forming likelihood-based confidence intervals for parameter estimates, correlations, indirect effects, and other derived parameters. Structural Equation Modeling: A Multidisciplinary Journal. 30(6), 985–999. https://doi.org/10.1080/10705511.2023.2183860

Falk, C. F. (2018). Are robust standard errors the best approach for interval estimation with nonnormal data in structural equation modeling? Structural Equation Modeling: A Multidisciplinary Journal, 25(2), 244-266. https://doi.org/10.1080/10705511.2017.1367254

Pek, J., & Wu, H. (2015). Profile likelihood-based confidence intervals and regions for structural equation models. Psychometrika, 80(4), 1123-1145. https://doi.org/10.1007/s11336-015-9461-1

Wu, H., & Neale, M. C. (2012). Adjusted confidence intervals for a bounded parameter. Behavior Genetics, 42(6), 886-898. https://doi.org/10.1007/s10519-012-9560-z

Issues

If you have any suggestions or found any bugs or limitations, please feel feel to open a GitHub issue. Thanks.