What Is PLS-SEM vs CB-SEM? Key Differences Explained
- CB-SEM (covariance-based SEM) estimates the model parameters so that the covariance matrix implied by the model is as close as possible to the observed covariance matrix. It usually relies on maximum likelihood estimation and treats constructs as common factors. Common software includes AMOS, LISREL, Mplus and R's lavaan.
- PLS-SEM (partial least squares SEM) is variance-based and composite-based. It aims to maximise the explained variance (R²) of the dependent constructs. Most management researchers run it in SmartPLS.
When to Use PLS-SEM in Your PhD Management Thesis
- Your goal is prediction or theory development. Examples include studies on emerging topics such as AI adoption, gig-work engagement or digital banking trust, where theory is still evolving.
- Your model includes formative constructs. These are indices built from their indicators, such as "service quality" measured through distinct dimensions.
- Your model is complex. Many constructs, mediators, moderators or higher-order constructs are handled well in PLS-SEM.
- Your sample is moderate. PLS-SEM converges with smaller samples, although that does not make a small sample adequate.
- Your data is non-normal. Bootstrapping in PLS-SEM does not assume a normal distribution.
When CB-SEM Is the Better Choice for Theory Testing
- You are testing well-established frameworks such as TAM, UTAUT or the Theory of Planned Behaviour in a new context.
- All your constructs are reflective, meaning the items are interchangeable expressions of one underlying factor.
- You need global model-fit statistics to support your claims.
- Your sample is large, typically 200 or more cases, with approximately normal data.
- You plan to run confirmatory factor analysis (CFA) and test measurement invariance across groups.
Sample Size, Data Normality & Model Fit: Quick Comparison
| Primary goal | Prediction, explanation | Theory confirmation |
| Sample size | Works with smaller samples; use the inverse square root method (Kock & Hadaya, 2018) or a power analysis | Usually 200+; larger for complex models |
| Data distribution | No normality assumption (bootstrapping) | ML assumes multivariate normality; robust estimators are available |
| Construct type | Reflective and formative | Mainly reflective |
| Model fit | Limited; SRMR is commonly reported (< 0.08) | Chi-square, CFI/TLI (≥ 0.90–0.95), RMSEA (≤ 0.06–0.08), SRMR (≤ 0.08) |
| Typical software | SmartPLS | AMOS, LISREL, lavaan, Mplus |
PLS-SEM or CB-SEM in 2026: Which Do Reviewers Prefer?
- Match the method to the aim. Use prediction for PLS-SEM and confirmation for CB-SEM.
- Cite methodological authorities. Examples include Hair et al. (2019, 2022) for PLS-SEM, and Kline's Principles and Practice of Structural Equation Modeling or Hu & Bentler (1999) for CB-SEM fit criteria.
- Report transparently. Include bootstrapping settings, HTMT, and either PLSpredict or full fit indices.
- Consider consistent PLS (PLSc) if you use PLS-SEM with purely reflective constructs.
Decision Checklist: PLS-SEM vs CB-SEM for PhD Thesis
- Prediction, complex model, formative constructs → PLS-SEM (SmartPLS)
- Theory confirmation, reflective constructs, large normal sample → CB-SEM (AMOS/lavaan)
- Unsure? Fix the decision in your project synopsis and get expert review before collecting data.
FAQs
A. Neither is best in all cases. PLS-SEM suits predictive and exploratory research, and CB-SEM suits confirmatory theory testing. Choose based on your research objective.
A. Use PLS-SEM for prediction, formative constructs, complex models or non-normal data. Use CB-SEM when testing established theory with a large sample and when global fit indices are required.
A. SmartPLS has a simpler interface for complex and predictive models. AMOS is the standard for CFA and fit-based confirmatory analysis. Your research aim should decide, not convenience.
A. PLS-SEM can run on smaller samples, but you still need adequate statistical power. Justify your sample size with a power analysis or the inverse square root method.
A. Yes, as long as each method serves a clearly stated purpose and the combination is justified in your methodology chapter.