Structural Equation Modeling (SEM) Help From a Statistics Professor
Structural Equation Modeling lets you test complex theories in a single, coherent model: latent constructs measured by multiple indicators, direct and indirect effects, and relationships among many variables at once. It is the method of choice for validating questionnaires and testing theoretical frameworks in psychology, management, marketing, education and health research.
SEM is also demanding. Models fail to converge, fit indices disagree, reviewers ask about measurement invariance and modification indices tempt you toward overfitting. Since 2014, I have helped researchers specify, estimate, evaluate and report SEM models that stand up to committee and peer review.
What I Can Help With
Confirmatory Factor Analysis (CFA)
- Specifying measurement models from theory or prior EFA
- Evaluating factor loadings, residual variances and correlated errors
- Construct reliability (composite reliability, omega) and validity (AVE, Fornell-Larcker, HTMT)
- Common method bias checks
- Second-order and bifactor models
Full Structural Models and Path Analysis
- Translating your conceptual framework into a testable path diagram
- Mediation with bootstrapped confidence intervals for indirect effects
- Moderation and moderated mediation, including latent interactions
- Comparing nested and non-nested competing models (χ² difference tests, AIC/BIC)
Advanced SEM
- Measurement invariance across groups: configural, metric, scalar and strict
- Multi-group SEM
- Latent growth curve models for longitudinal data
- Handling missing data with FIML and non-normal data with robust estimators (MLR, WLSMV for ordinal indicators)
- PLS-SEM with SmartPLS, and when it is or is not appropriate compared with covariance-based SEM
Evaluating Model Fit, Properly
No single index tells the whole story. I help you report and interpret a balanced set:
| Index | Commonly cited guideline |
|---|---|
| χ² test | Non-significant suggests good fit, but is sensitive to large samples |
| CFI / TLI | ≥ .90 acceptable; ≥ .95 good |
| RMSEA (with 90% CI) | ≤ .06–.08 acceptable |
| SRMR | ≤ .08 |
These are guidelines, not laws. I help you justify your evaluation with appropriate citations and, when fit is poor, diagnose the cause using theory, not just modification indices.
Reporting SEM Results
Publication- and dissertation-ready reporting includes the estimator, how missing data was handled, fit indices, standardized estimates with standard errors, indirect effects with bootstrapped confidence intervals and a clear path diagram. I help you produce all of it in APA 7 style.
SEM Software I Support
- SPSS AMOS: graphical model building (SPSS help)
- R with lavaan and semTools: flexible, reproducible and free (R help)
- Stata
semandgsem(Stata help) - SmartPLS for PLS-SEM
- Interpreting Mplus syntax and output
SEM builds on regression and factor analysis. If those foundations feel shaky, we strengthen them first.
Get Expert SEM Support
Whether you are designing your first CFA or responding to reviewers on a complex structural model, book a free 15-minute consultation. Share your conceptual model, your sample size, your software and your deadline, and you will receive a clear plan and quote within 24 hours.
Prefer email or chat? Write to [email protected] or message me on WhatsApp at +1 (425) 999-3993.