Abstract
Sharifi and Hassaskhah (2011) set out to investigate the impact of portfolio assessment techniques on the overall quality of students' writing. The population of the study included 20 university students in a time interval extending over one semester at the University of Guilan, Iran. In this review I'm going to summarize this study in terms of its research design and the results reached by the researchers. The two dimensions of this research will then be discussed in terms of their descriptive power, explanatory adequacy and external validity.