This article makes two simple observations about high-stakes assessments. The first is that, because mathematics is a very technical subject, an assessment item can be mathematically flawed regardless of how elementary it is. For this reason, every assessment project needs the active participation of high level mathematicians. A second point is that high-stakes assessments are inherently a very blunt instrument because they are incapable of accurately measuring the most important aspect of mathematics achievement: sustained sequential thinking. Because the general public and policymakers are not aware of this fact, they tend to read more into such assessment scores than such a limited instrument can deliver. If we want high-stakes assessments to have a positive influence on mathematics education, this article suggests that we should reorient our thinking about how much student achievement such assessments can reliably measure, which is "not very much."