In much educational literature it is recognised that the broader social conditions in which teachers live and work, and the personal and professional elements of teachers' lives, experiences, beliefs and practices are integral to one another, and that there are often tensions between these which impact to a greater or lesser extent upon teachers' sense of self or identity. If identity is a key influencing factor on teachers' sense of purpose, self‐efficacy, motivation, commitment, job satisfaction and effectiveness, then investigation of those factors which influence positively and negatively, the contexts in which these occur and the consequences for practice, is essential. Surprisingly, although notions of ‘self’ and personal identity are much used in educational research and theory, critical engagement with individual teachers' cognitive and emotional ‘selves’ has been relatively rare. Yet such engagement is important to all with an interest in raising and sustaining standards of teaching, particularly in centralist reform contexts which threaten to destabilise long‐held beliefs and practices. This article addresses the issue of teacher identities by drawing together research which examines the nature of the relationships between social structures and individual agency; between notions of a socially constructed, and therefore contingent and ever‐remade, ‘self’, and a ‘self’ with dispositions, attitudes and behavioural responses which are durable and relatively stable; and between cognitive and emotional identities. Drawing upon existing research literature and findings from a four‐year Department for Education and Skills funded project with 300 teachers in 100 schools which investigated variations in teachers' work and lives and their effects on pupils (VITAE), it finds that identities are neither intrinsically stable nor intrinsically fragmented, as earlier literature suggests. Rather, teacher identities may be more, or less, stable and more or less fragmented at different times and in different ways according to a number of life, career and situational factors.

This paper draws on findings from a four‐year longitudinal research project, commissioned by the Department for Education and Skills (DfES), which investigated Variations in Teachers’ Work, Lives and Effectiveness (VITAE). Drawing on data gathered from 300 teachers working in 100 primary and secondary schools in England, the research identified associations between commitment and effectiveness (perceived and in terms of pupil attainment) and found that there were more, and less, effective teachers in each of six professional life phases. It found that teachers in each of these phases experienced a number of different scenarios that challenged their abilities to sustain their commitment (i.e. remain resilient). This paper discusses how these impact, positively and negatively, on teachers’ capacities for sustaining their initial commitment and associations between identity, well‐being and effectiveness. It finds that teacher identities are neither intrinsically stable nor intrinsically fragmented, but that they can be more, or less, stable and more or less fragmented at different times and in different ways according to the influence of the interaction of a number of personal, professional and situated factors. The extent to which teachers are able to and are supported in managing the scenarios they experience will determine their sense of effectiveness.

This article outlines the research design of a large‐scale, longitudinal research study in England intended to describe and explore variations in teachers' work, lives and their effects on pupils' educational outcomes. The study, funded by the Department for Education and Skills (DfES) and incorporated into the Teaching and Learning Research Programme (TLRP) as an ‘Associate Project’, used an innovative mixed‐methods research design to create case studies of 300 teachers in Years 2, 6 and 9. The research was conducted over three consecutive academic years and collected a wide range of data through interviews, questionnaire surveys of teachers' and pupils' views and assessment data on pupils' attainments in English and mathematics. The text summarises the main findings from the research in relation to four interconnected themes of the study: Professional Life Phases; Professional Identity; Relative Effectiveness; and Resilience and Commitment. The influence of school context, in terms of level of social disadvantage of pupil intake, is also investigated. Key findings and their implications for policy and practice are highlighted.

This paper extends the introduction to the authors’ study of successful school leadership and how it influences pupil outcomes begun in the Editorial introduction. Critical to an appreciation especially of the external validity of their results is an understanding of the policy context in which the English leaders in their study found themselves; this is a policy context dominated by concerns for external accountability and increases in the academic performance of pupils. In addition to describing this context, the paper summarises the conceptual and methodological framework that guided the early stage of their research and outlines their mixed-methods research design.