Augustin Mutak was born in 1994 in Zagreb, Croatia. He grew up in the town of Zaprešić, located next to Zagreb, where he attended elementary school and high school.
He studied both for his bachelor’s (2013 - 2016) and his master's degrees (2016 – 2018) in psychology at the University of Zagreb, Faculty of Humanities and Social Sciences. Already during his student days he started to be an active researcher, having won the Rector’s Award for student research in his second year of bachelor’s. He continued doing research throughout his studies and has been elected for two consecutive years (2016 – 2018) for the Leader of the Research section of Psychology Students’ Club at his faculty. His research interests at that time focused on the rhythmic variations of mood, with his focus broadening to include psychometric topics towards the end of his studies.
He was one of the founding members and a member of the first Editorial board of Psychē, the journal of the Psychology Students’ Club at the Faculty of Humanities and Social Sciences, University of Zagreb.
Augustin was a member of the Junior Researcher Programme in the 2017/18 cohort, where he participated in a project which aimed to assess the validity of certain methods in social media research.
He was also the Finance Officer of the Junior Researcher Programme (2017 – 2019) and the Senior Finance Officer (2019 – 2020).
Augustin was also active in the local community in his town of Zaprešić. For three consecutive years (2015 – 2018) he was the President of the Association of Students of the City of Zaprešić, where he initiated the process of revitalization of the association after a longer period of inactivity and secured funding for the association’s projects. Through the local student association, he also initiated the processes of improvement of the scholarship system in Zaprešić and lowering of the public transport fee for students. He was also a member of the local Youth Council (2017 – 2020) and was one of the delegates of his town’s Youth Council to the Coordination of Youth Councils of Republic of Croatia. From 2018 until 2023 he was in the Management board of the Youth centre “CeZaM”, another association from Zaprešić.
Augustin graduated in 2018 on the topic of “Psychometric analysis of the usability of the lower asymptote parameter in graded response model for detecting socially desirable responding”.
After obtaining his master’s degree, Augustin went for a two-month academic visit to the University of Oxford. At Oxford, he participated in a project which aimed to investigate the trajectories of well-being over multiple years in different countries using large-scale datasets.
After returning from Oxford, Augustin founded his private business “Psihometar” in a form of a sole proprietorship in late 2018, which aimed to provide the services of statistical and psychometric data analysis to clients. Psihometar attracted various domestic clients, such as the Youth and Children Protection Polyclinic in Zagreb, but also various foreign clients, such as the Griffith University, Queensland, Australia.
He operated his private business for 2.5 years until enrolling in doctoral studies at Freie Universität Berlin in 2021. Today Augustin resides in Potsdam and studies and works at Freie Universität Berlin, where he participates in a project which aims to develop and validate new psychometric models which relax the assumptions of current widely used item response theory models which include response time data (such as the assumptions of stationarity and conditional independence).
Augustin is an avid user of R and especially of tidyverse packages. He also developed the R package cosinor2, which provides tools for fitting sine curves to data to measure rhythmicity at population level. The cosinor2 package has around 29,000 downloads on CRAN. Besides R, Augustin also uses Stan, where he has particular knowledge of the reparameterization of complex models.
Augustin has five scientific articles published in peer-reviewed journals. He has had presentations on seven scientific conferences (four of which were just student conferences).
In his free time, he likes traveling to and exploring various cities with his car, mapping Zaprešić and Potsdam on OpenStreetMap and playing games from the Anno series.

Research Interests

• Psychometric model development
• Scale validation
• Rhythmicity of mood

Research Projects

• Test-taking engagement and test-taking behavior: Modeling the processes underlying item nonresponse and guessing (DFG project number 288472689)

• Mutak, A., Krause, R., Ulitzsch, E., Much, S., Ranger, J., & Pohl, S. (in press). Modeling the intraindividual relation of ability and speed within a test. Journal of Educational Measurement.

• Ranger, J., Wolgast, A., Much, S., Mutak, A., Krause, R., & Pohl, S. (in press). Disentangling different aspects of change in tests with the D-Diffusion model. Multivariate Behavioral Research.

• Jarke H., Jakob L., Bojanić L., García-Garzón E., Mareva S., Mutak A. & Gjorgjiovska, J. (2022) Registered report: How open do you want your science? An international investigation into knowledge and attitudes of psychology students. PLoS ONE, 17(2): e0261260. https://doi.org/10.1371/journal.pone.0261260

• Orben, A. C., Mutak, A., Dablander, F., Hecht, M., Krawiec, J. M., Valkovičová, N. & Kosīte, D. (2018). From Face-to-Face to Facebook: Probing the Effects of Passive Consumption on Interpersonal Attraction. Frontiers in Psychology, 9, Article 1163. https://doi.org/10.3389/fpsyg.2018.01163

• Mutak, A., Vranić, A. (2017). Utjecaj stupnja uglazbljenosti teksta na upamćivanje teksta [The influence of the degree of musical accompaniment of text on remembering text]. Psihologijske teme, 26(2), 309-333. https://doi.org/10.31820/pt.26.2.3

• Mutak, A., Vukasović Hlupić, T. (2017). Exogeneity of the circaseptan mood rhythm and its relation to the working week. Review of psychology, 24(1-2), 15-28. https://doi.org/10.21465/rp0024.0002

• Mutak, A. (2017). Rhythmic variations of mood. Gyrus, 4(3-4), 304-310.