This dissertation investigates the ways in which pre-k teachers understood the math content that they were to teach and their math instruction. To investigate this, a qualitative case study examining five pre-k teachers was conducted. Data sources included observation field notes, teacher interviews, and documents such as state and district pre-k guidelines. The findings from this dissertation suggest that pre-k teachers’ knowledge entails both knowledge of subject matter and pedagogical content knowledge. In addition, this study identified what these pre-k teachers knew about math and teaching/learning math as well as what they still needed to know to provide high quality and effective math instruction. Chapter 1 introduces my research question and important terms, such as mathematical knowledge for teaching (MKT). Chapter 2 synthesizes relevant literature in the area of effective math instruction, theoretical framework of teachers’ mathematical knowledge for teaching and early mathematics education. The literature review seeks to highlight the importance of early childhood teachers’ deep understanding of mathematical content and of their math instruction. Chapter 3 forwards the specific conceptual framework for this study while detailing the methodology that guided this investigation including data gathering and analysis. Chapter 4 presents the findings from this research. It examines pre-k teachers’ understanding of mathematical content that they are to teach and their knowledge of how to teach mathematics. Chapter 5 addresses the significance of these two major findings. First, I discuss the four types of mathematical knowledge and skills that these pre-k teachers possess. I also compare and contrast them with the teacher knowledge examined in the literature. Then, by examining research literature on early math education, I suggest what mathematical knowledge and skills they still need to attain to offer high-quality and effective math instruction. This dissertation concludes with a discussion of implication for teachers, teacher educators, and suggestions for future research. / text

Aufgrund der Vorhersagekraft früher mathematischer Kompetenzen für spätere Schulleistungen beschäftigt sich die Forschung mit der Identifikation möglicher Einflussfaktoren der mathematischen Kompetenzentwicklung von Kindern vor Schuleintritt. Da der Großteil der drei- bis sechsjährigen Kinder in Deutschland eine Kindertagesstätte besucht, ist in diesem Zusammenhang die pädagogische Qualität frühkindlicher Bildungseinrichtungen in den Fokus gerückt. Einen wichtigen Aspekt dieser Qualität stellen frühpädagogische Fachkräfte dar. Sie werden als Interaktionspartner:innen von Kindern als potenzieller Einflussfaktor hinsichtlich deren mathematischer Kompetenzentwicklung betrachtet. Im Rahmen der Forschung zur professionellen Kompetenz frühpädagogischer Fachkräfte in Mathematik setzt man sich mit der Frage auseinander, welche Merkmale eine kompetente Fachkraft auszeichnen und inwiefern diese die mathematische Kompetenzentwicklung von Kindern beeinflussen. Während in den letzten Jahren vermehrt die Entwicklung sowie das Zusammenspiel einzelner Facetten professioneller Kompetenz frühpädagogischer Fachkräfte untersucht worden sind, werden Kinder bislang kaum in wissenschaftliche Studien einbezogen. Die vorliegende Dissertation schließt diese Forschungslücke und untersucht die Vorhersagekraft der Kompetenzfacetten Dispositionen und Performanz im Hinblick auf die mathematische Kompetenzentwicklung von Kindern. Damit dies möglich ist, wird im Rahmen der vorliegenden Arbeit ein Beobachtungsinstrument zum Erfassen der Performanz frühpädagogischer Fachkräfte entwickelt. Die Ergebnisse zeigen, dass sich die Performanz mithilfe des entwickelten Beobachtungsinstruments zuverlässig erfassen lässt. Weiterhin sagt die Performanz die mathematische Kompetenzentwicklung von Kindern voraus, während dies für die erhobenen Dispositionen nicht gilt. Für den nationalen Forschungsraum handelt es sich hierbei um die ersten beziehungsweise einige der wenigen evidenzbasierten Forschungsergebnisse. / Due to the predictive power of early mathematical skills for later academic achievement, research has been addressing the identification of potential factors influencing children's mathematical development prior to school entry. Since the majority of three- to six-year-old children in Germany attends pre¬schools, the pedagogical quality of early childhood and care institutions has come into focus. One important aspect of pedagogical quality are early childhood educators. They are regarded as a potential influencing factor for children’s mathematical development. Therefore, research on professional competence of early childhood educators in mathematics delves into identifying the characteristics which distinguish competent early childhood educators and how these characteristics may potentially influence children’s mathematical development. While the development and interplay between different facets of professional competence have been a major concern of research in recent years, children have hardly been included in scientific studies. This dissertation closes this research gap and examines the predictive power of dispositions and performance, both which are facets of professional competence, for children’s mathematical development. In order to achieve this, an observation instrument assessing early childhood educators’ performance has been developed. The results show that early childhood teachers’ performance can be measured reliably using the developed observation instrument. Furthermore, performance predicts children’s mathematical development while this is not the case for early childhood teachers’ dispositions. Within the national research context, these results are among the first evidence-based research findings that outline the relationship between distinct facets of early child¬hood educators’ professional competence and children’s mathematical development.