What Is the Maximum Likelihood Estimate When the Initial Solution to the Optimization Problem Is Inadmissible? The Case of Negatively Estimated Variances

Authors: Steffen Zitzmann, Julia-Kim Walther, Martin Hecht, Benjamin Nagengast

Source: Psych, Vol 4, Iss 3, Pp 343-356 (2022)

Subject Terms: maximum likelihood, Heywood case, inadmissible solution, confirmatory factor analysis, Psychology, BF1-990

File Description: electronic resource

Relation: https://www.mdpi.com/2624-8611/4/3/29; https://doaj.org/toc/2624-8611

Access URL: https://doaj.org/article/f1212a6c2e714e3db61399192947f1b0

Shrinking Small Sample Problems in Multilevel Structural Equation Modeling via Regularization of the Sample Covariance Matrix

Authors: Julia-Kim Walther (ORCID 0000-0001-5758-1211), Martin Hecht (ORCID 0000-0002-5168-4911), Steffen Zitzmann (ORCID 0000-0002-7595-4736)

Source: Structural Equation Modeling: A Multidisciplinary Journal. 2025 32(1):46-65.

Peer Reviewed: Y

Page Count: 20

Descriptors: Sample Size, Hierarchical Linear Modeling, Structural Equation Models, Matrices, Computation, Correlation, Simulation, Evaluation Criteria, Accuracy

To Be Long or to Be Wide: How Data Format Influences Convergence and Estimation Accuracy in Multilevel Structural Equation Modeling

Authors: Julia-Kim Walther (ORCID 0000-0001-5758-1211), Martin Hecht (ORCID 0000-0002-5168-4911), Benjamin Nagengast (ORCID 0000-0001-9868-8322), Steffen Zitzmann (ORCID 0000-0002-7595-4736)

Source: Structural Equation Modeling: A Multidisciplinary Journal. 2024 31(5):759-774.

Peer Reviewed: Y

Page Count: 16

Descriptors: Data, Monte Carlo Methods, Statistical Distributions, Matrices, Statistical Analysis, Predictor Variables, Structural Equation Models, Factor Analysis, Equations (Mathematics)

Finding the Optimal Number of Persons (N) and Time Points (T) for Maximal Power in Dynamic Longitudinal Models Given a Fixed Budget

Authors: Martin Hecht (ORCID 0000-0002-5168-4911), Julia-Kim Walther (ORCID 0000-0001-5758-1211), Manuel Arnold (ORCID 0000-0002-1623-2565), Steffen Zitzmann (ORCID 0000-0002-7595-4736)

Source: Structural Equation Modeling: A Multidisciplinary Journal. 2024 31(3):535-551.

Peer Reviewed: Y

Page Count: 17

Descriptors: Longitudinal Studies, Best Practices, Operating Expenses, Research Design, Sample Size, Time Management, Statistical Analysis