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Technical & algorithm documentationIndependently benchmarked

Covariance-based SEM workflow

Extend an approved CFA into a recursive latent structural model.

Overview

CB-SEM jointly estimates a validated reflective measurement model and a researcher-specified recursive latent structural model.

Theoretical foundation

The structural model relates endogenous latent variables to other latent variables and disturbances. Direct effects are structural coefficients; indirect effects are products and sums across directed paths; total effects combine direct and indirect effects.

Key equations

Latent structural model
\eta=B\eta+\Gamma\xi+\zeta

Algorithm and computation

Survlytics reuses an approved CFA revision, accepts only acyclic directed construct paths, includes covariances among exogenous factors, and fits the joint model through semopy MLW/SLSQP on listwise-complete continuous indicators. It reports fit, standardised and unstandardised paths, direct/indirect/total effects, latent R², residuals, convergence and admissibility.

Required data

An approved CFA measurement model, identified reflective constructs, at least one acyclic structural path and sufficient complete continuous-indicator observations.

Assumptions

The measurement model is credible, the recursive path structure is theory-defined, observations are independent, and normal-theory ML is suitable.

Available settings

Approved measurement-model revision; recursive path specification; confidence/display settings inherited from the validated workflow.

Worked example

The frozen benchmark uses three latent factors and paths F1 → F2, F1 → F3 and F2 → F3 for N = 800 synthetic observations.

Limitations and non-claims

No feedback loops, categorical outcomes, robust ML, FIML, equality constraints, multigroup SEM or causal identification are implemented. Arrows do not establish causality.

Validation notes

A frozen R 4.5.2/lavaan 0.7-2 fixture compares fit, paths, loadings, indirect/total effects and latent R². Fit and standardised estimates use absolute tolerance 0.002; AIC/BIC use 0.02.

How Surv.lytics computes Covariance-based SEM
EstimatorJoint recursive latent MLW model
Librariessemopy 2.3.11; SciPy 1.17.0
Missing dataListwise
ValidationIndependently benchmarked
Defaults{'estimator': 'MLW', 'recursive': True}
Pass
Recursive three-factor CB-SEM versus lavaan

PASS: frozen reference statistics agree within the declared tolerances. Tolerance: 0.002 for fit/standardised estimates; 0.02 for AIC/BIC Known differences: Only supported recursive continuous-indicator models are covered.

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References and verification status

  1. Fornell, C., & Larcker, D. F. (1981). Evaluating structural equation models with unobservable variables and measurement error. Journal of Marketing Research, 18(1), 39–50. https://doi.org/10.2307/3151312

    VerifiedOpen DOI
  2. Hu, L., & Bentler, P. M. (1999). Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives. Structural Equation Modeling, 6(1), 1–55. https://doi.org/10.1080/10705519909540118

    Unverified draftOpen DOI

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