Since 2006 Swedish compulsory school teachers are required to use individual developmentplans (IDPs) as part of their assessment practices. The IDP has developed through two major reforms and is currently about to undergo a third in which requirements for documentation are to be reduced. The original purpose of IDP was formative: a document containing targets and strategies for the student's future learning was to be drawn up at the parent-pupil-teacher meetingeach semester. The 2008 reform added requirements for written summative assessments/grade-like symbols to be used in the plan. This thesis aims to generate knowledge of the IDP as a tool in terms of what characterizes IDP documents as well as teachers' descriptions of continuous IDP work. It contains four articles. The first two are based on 379 collected IDP documents from all stages of compulsoryschool, and the last two build on interviews with 15 teachers. Throughout, qualitative content analysis has been used for processing data. The analytical framework comprises Latour's conceptual pair inscription – translation, Wartofsky's notions of primary/secondary/tertiary artifacts, and Wertsch's distinction between mastery and appropriation, which together provide an overall framework for understanding how the IDP becomes a contextually shaped tool that mediates teachers' actions in practice. Moreover, the activity theoretical concept of contradictionis used to understand and discuss dilemmas teachers experience in relation to IDP. In article 1, targets and strategies for future learning given to students are investigated and discussed in relation to definitions of formative assessment. Concepts were derived from the data and used for creating a typology of target and strategy types related either to being aspects (students' behavior/attitudes/personalities) or to subject matter learning. In article 2, the distribution of being and learning targets to boys and girls, respectively, is investigated. The results point to a significant gendered difference in the distribution of being targets. Possible reasons for the gendered distribution are discussed from a doing-gender perspective, and the proportion of being targets in IDPs is discussed from an assessment validity point of view. In article 3, teachers' continuous work with IDPs is explored, and it is suggested that IDP work develops in relation to perceived purposes and the contextual conditions framing teachers' work. Three qualitatively different ways of perceiving and working with IDP are described in a typology. Article 4 elaborates on dilemmas that teachers experience in relation to IDP, concerning time, communication, and assessment. A tentative categorization of dilemma management strategies is also presented. Results are synthesized in the final part of the thesis, where the ways in which documents are written and IDP work is carried out are discussed as being shaped in the intersection between rules and guidelines at national, municipal and local school level, and companies creating solutions for IDP documentation. Various purposes are to be achieved with the help of the IDP, which makes it a potential field of tension that is not always easy for teachers to navigate. Several IDP-related difficulties, but also opportunities and affordances, are visualized in the studies of this thesis. / <p>Svensk sammanfattning: s. 111-126.</p>