General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.-Users may download and print one copy of any publication from the public portal for the purpose of private study or research. -You may not further distribute the material or use it for any profit-making activity or commercial gain -You may freely distribute the URL identifying the publication in the public portal -ing me with the opportunity and freedom to conduct research following my own ideas (with some necessary boundaries!).In addition, I want to thank Professor Hanne Kathrine Krogstrup, former head of our research group CaBE (Capacity Building and Evaluation), for believing in my abilities and for promoting a healthy and stimulating culture for PhD students at our department. Furthermore, I wish to thank my skilled co-supervisor, Associate Professor Antonia Scholkmann, for introducing me to the entertaining and creative (sometimes utterly crazy) work by Professor Andy Field along with some core books on SEM that catapulted me into new statistical territory. Without these valuable resources, I would not have had the courage to apply advanced multivariate methods. Thank you for reading parts of my manuscript and for providing me with novel and useful ideas on both the content and structure of my research articles. Moreover, I want to thank Professor Annette Lorentsen and Associate Professor Lars Bang Jensen for their committed work on Program for Learning Management (PLM). It was exciting and instructive to work alongside fellow PhD students. Without this collaboration, my dissertation would not have been the same. VI I also want to express my gratitude to the entire research group of CaBE, including the new head of the group, Professor Julie Borup Jensen, for her committed work and inclusive style of leadership, which fosters creativity and mutual respect between colleagues. In addition, I wish to thank researchers at SePU (Senter for Praksisrettet Utdanningsforskning) in Hamar, Norway, for providing information on the impressive dataset, which is presently the largest in Danish education history. Thanks to Professor Thomas Nordahl for his immensely helpful course on quantitative research in education. I also wish to thank all students, parents, and teachers who made this research possible by participating in PLM's surveys. Without your responses, I would have had nothing to analyze, no findings to report, and no conclusions to draw.Finally, I wish to thank my family and friends, including my supportive parents, Allan and Lene, my big brother, Kristian and his girlfriend, Christa, and their smiling newborn son, Manfred. I also wish to personally thank my girlfriend, Laerke Pilgaard. Thank you for your kind words, support, and lovewithout it, I would not have managed to complete my dissertation. Hopefully, this dissertatio...