This interpretive study of the implementation of a school-based assessment scheme of biology practical work in Hong Kong examines three teachers' struggles with the issue of fairness in relation to their classroom actions. Though the teachers' discourses were dominated by, and their classroom actions were pre-eminently influenced by, the notion of fairness, they did so in three qualitatively different ways: (1) fair in the sense of assessing students on a fair basis; (2) fair in the sense of not jeopardizing students' chances to learn the subject matter while they are being assessed; and (3) fair in the sense of not depriving students' of opportunities of receiving all-round education. The implication is that assessment innovation is a necessary, but not a sufficient, mechanism for changes within our educational system. The role of the teacher is challenged by the new assessment scheme—the co-existence of assessment and learning requires a significant change in the teacher's pedagogy. For teachers to implement the new programme their existing understanding and beliefs concerning assessment must be challenged and opportunities provided for them to come to terms with the philosophy of the new assessment scheme. Most importantly, the teachers themselves must undertake such a learning process. [Copyright of International Journal of Science Education is the property of Routledge. Full article may be available at the publisher's website: http://dx.doi.org/10.1080/09500690010017129]
