‘Learning study’ is usually described as a hybrid between, on the one hand, design experiments (Brown, 1992, Cobb et.al. 2003) and, on the other, the Japanese lesson study tradition (Marton & Pang, 2006, Runesson 2008). While certain aspects of learning studies are similar to design experiments (such as grounding the design in a learning theory) others (such as teachers designing the teaching in relation to specific objects of learning) is more like lesson studies (Lewis, 2000). In my contribution I will discuss learning study as a research model for domain specific teacher research. The focus will be on the development of the theoretical understanding of the objects of learning as well as teaching-learning relations within specific subject areas. Based on an analysis of some examples of learning studies I will show how the analysis of critical aspects of the learning object as well as the iterative design can be described as a process of transaction resulting in a specification of the meaning of the learning object (Dewey and Bentley, 1948, Carlgren, 2010)