Deciding how many factors to retain is still the weakest link in most scale development studies. I run large Monte Carlo simulations to see how classical and modern methods (parallel analysis, exploratory graph analysis, Hull, comparison data, empirical Kaiser) behave under conditions researchers actually face:
Related work: Kaçak & Kılıç (2025, IJATE); Kaçak, Temurtaş & Kılıç (2025, Psihologija); MSc thesis (2024).
Coefficient alpha and omega are reported almost automatically. I look at what happens to them when the assumptions behind them fail — missing data and the way it is handled, correlated errors, and item wording effects.
Related work: Kaçak & Kılıç (2024, JMEEP); Kılıç, Acar Güvendir, Güler & Kaçak (2025, Measurement: IRP).
Cross-country comparisons only mean something if the instrument measures the same thing everywhere. I work on measurement invariance (MGCFA, alignment optimization, psychometric networks) and on item-format effects, using PISA, PIRLS, TIMSS and ICILS data.
Related work: Ekici & Kaçak (2026, JTELL); ICILS 2023 invariance study (under review); TIMSS 2023 item-format study (Balkan Congress, 2025).
Kaçak, T. Factor retention under careless responding: A Monte Carlo comparison of traditional and random-intercept adjusted dimensionality assessment methods. Multivariate Behavioral Research With editor
Güler, G., & Kaçak, T. Does item wording effect change the psychometric properties of a scale? An investigation with the Warwick–Edinburgh Mental Well-Being Scale. Journal of Survey Statistics and Methodology Under review
Kaçak, T. The effects of item format and cognitive domain interaction on students’ mathematics performance in TIMSS 2023: A cross-country study. Studies in Educational Evaluation Under review
Kaçak, T. Do test-taking engagement and test delivery mode matter? Modeling the interaction effects on DASS-42 with polytomous explanatory IRT. Journal of Social Research Methodology Under review
Kaçak, T., & Kılıç, A. F. Structuring psychopathology: A stress-test of factor retention methods in complex hierarchical models. Journal of Assessment Under review
Güler, G., Acar Güvendir, M., Kılıç, A. F., Aktaş, M., & Kaçak, T. Within-subjects measurement invariance testing across survey mode and incentive conditions: A longitudinal CFA approach. European Journal of Psychological Assessment Under review
| Year | Degree | Institution |
|---|---|---|
| 2025 – present | PhD, Educational Measurement and Evaluation | Hacettepe University |
| 2024 | MSc, Educational Measurement and Evaluation | Hacettepe University |
| 2021 | BSc, Primary School Education (GPA 3.51) | Anadolu University |
MSc thesis. Comparison of factor retention methods in exploratory factor analysis under various conditions. Read it at the Turkish Council of Higher Education thesis center.