Taking stock of portfolio assessment scholarship: From research to practice

•There remains a research-practice gap in portfolio assessment scholarship.•Portfolio assessment research can inform writing pedagogy and assessment practices.•Writing portfolio assessment has potential to promote reflection and metacognition.•Training on setting up context-specific portfolio programmes remains underdeveloped.•Using portfolios to support reflection becomes popular in L2 writing classes.

Portfolio assessment has been extensively investigated over the past two decades. Nonetheless, its broader applications in the first and second language writing classrooms remain inadequate. This paper emphasizes that theoretical and empirical research evidence is likely to inform the classroom-based implementation of portfolio assessment. The paper first introduces the origin, definitions, rationale, applications and characteristics of portfolio assessment, and then historicizes writing portfolio assessment scholarship according to the evolving trends of portfolio assessment development in both the first and second language writing contexts. Subsequently, a method section is included concerning how the theoretical and empirical scholarship was screened, selected and categorized for review in terms of three key themes: (1) research which supports classroom applications of portfolio assessment; (2) research which inhibits classroom-based portfolio assessment practices; and (3) research that needs future investigation on how to promulgate portfolio implementation. The review is followed by three pedagogical recommendations suggesting how teachers, administrators and programme directors can better develop learning-supportive portfolio assessment practices and have maximum exposure to pertinent professional learning. It is hoped that the paper advances the portfolio assessment scholarship, predominantly with a view of using research evidence to inform classroom practices.