Throughout this era of greater educational accountability, assessment researchers have argued that large-scale comparative assessment data can enhance learning within and across systems of education and can foster reforms based on the practices of high achieving jurisdictions. Other researchers are less optimistic, warning that educational reform is fraught with danger. This paper explores an unsuccessful British Columbia Ministry of Education initiative to reform its mathematics curricula. This case study illustrates the myriad factors which prevent the success of planned reforms. (Contains 2 footnotes.)