Description: In various countries we have seen widespread support for "evidence-based" and "best" practice in conjunction with developments in countries (e.g., UK, Australia, Canada, USA) such as the United States with policies as the No Child Left Behind (NCLB) legislation, the synthesis reports offered by the National Reading Panel (NRP) and others (e.g., Snow, Burns and Griffin, 1998) as well as increased support for a narrower band of research (Reading Excellence Act; National Research Council, 1998, 1999, 2002) and the advent of Adequately Yearly Progress (AYP) and failing schools (Linn, Baker, Betebenner, 2001). Politicians seem to be persuaded that the shift to evidence-based practices informed by synthesis panels periodically reviewing preferably randomized "scientific studies will/may enable education to advance dramatically." (Slavin, 2002) The call to "scientific research" has been subjected to critique in our field on a number of grounds from the definition of science to the political motivations to specific studies that are accessed and cited, the types of findings that are touted, the legislation and reform models to which it has been coupled and the impact upon teachers, students and parents (e.g., Allington, 2002: Coles, 2002, Pressley, 2001, Shannon, Edmonson, O'Brien, 2001; Taylor, 1998; Tierney, 2001) My goal in this paper is to focus on the notion of evidence-based practice, which has been aligned with developments occurring or proposed in conjunction with educational reform efforts-most notably with legislated policy defining "scientific research" and subsequent specification of selected evidence-based practices to define what is and is not tenable, fundable or allowable in schools. In particular, I am interested in examining evidence-based research from the perspective of how practitioners might or might not be supported to use "scientifically based research" to inform practice. Methodology: The paper will draw on a historic analysis tied to an examination of policy development and studies of practice with a special focus upon how teachers are being positioned relative to knowledge in their practices-especially in literacy education. A careful examination of various documents (policy statements, legislation, essays exploring syntheses of research focussing upon practice) will occur across selected countries. These analyses will explore how and what kinds of educational research is positioned as informing the teaching of literacy. Conclusions: In general terms,. the discourse around "evidence-based" and "best" practice, tis seen as privileging certain research and notions of literacy and the position of the teacher is varied in accordance with the level of professional autonomy/responsibility that he or she is afforded. In terms of the latter, the range is from a role as conduit who delivers a preset program to a practitioner whose is responsible for developing and delivering a curriculum enlisting practices deemed scientifically sound to the role of an critical observer and autonomous professional. In conjunction with a narrowing of what counts as research and knowledge that might inform instruction, advocates of the a priori randomized groups comparison view the teacher variable as an influence that they would like to mute, dilute or balance across groups. At times the ideal study would allow for the implementation of treatment conditions, which are free or not contaminated by the influence of teachers. Yet the attempts to implement instructional programs and research these programs has reinforced the need for teachers to be creative, reflective and responsive decision makers. This also contrasts with studies of variations of treatments administered to randomized groups in a systematic fashion require a distortions in terms of how students are grouped, learnings experienced and literacies engaged (e.g., Warburton & Warburton, 2001). What might be important to control could be salient to learning or meeting the needs of students over time and across settings. Researchers may not be as open, as teachers need to be, to the shifts that occur over time in the implementation of a practice in different ways with different teachers, student(s) and others, and their impacts in an ongoing fashion and in a manner which may not have been foreseen in terms of possible impacts. It is noteworthy that this form of dynamic teacher decision making is consistent with how meaning-making in teaching occurs: as active meaning making teaching is transacted with due consideration to the students in different situations and informed by various observations and engagements with communities and possibilizing about literacies, learning and a range of practices (Brown, Duguid, Collins 1989). The meanings that teachers make would be unlikely to arise solely from syntheses of past narrowly defined empirical research for which notions of literacy and classrooms are so constrained. An over-reliance on past, traditional empiricism and overly prescriptive evidence-based practices is a form of retreating to a model of teaching that can be standardized and a teaching of literacy that fails to deal with socio-cultural dimensions. In so doing we are defining literacies and students learning potentials in a manner that ignores many of the dimensions that teachers and researchers need to contemplate while working together.