The ability to communicate--orally and in writing--is a graduate attribute that employers in many countries rank as number one in importance, aside from relevant qualifications. This paper reports the implementation and evaluation of a collaborative peer assessment and self-assessment learning and teaching (L&T) initiative, which was designed to improve postgraduate students' judgment of writing standards and to improve their own writing--according to that standard. The initiative was embedded in an introductory financial accounting unit in an Australian university. In a mixed methods study, the matched pair design revealed improvements in the written communication skills of students as determined by an independent assessor. There was also statistically significant improvement in the ability of students to apply assessment standards to grammatical, structural and presentation components of written communication. Whereas it was not possible to attribute the improvements entirely to the collaborative peer assessment initiative, our observations and students' self-reporting comments suggest that the L&T initiative was effective.