Choosing a curriculum for classroom use is always difficult. This is especially the case in mathematics, where there have been major controversies, sometimes called the � math wars� where opponents of standards-based curricula make arguments using data from less direct comparisons than those referred to in this paper.

The first question is, what do you want students to learn? This is controversial � different states have different standards, focusing on everything from the traditional curriculum (which focuses on the mastery of fundamental skills and understandings) to �reform� or �standards-based� curricula (which have a broader range of goals covering skills, concepts, and problem solving).

Once you decide on fundamental goals for instruction the question is, �What works?� What evidence is there that any particular curriculum or group of curricula is more or less effective at having students learn the desired skills?

Our purpose in producing this tool is to describe the controversies, identify the relevant curricula and resources for evaluating them, and summarize the (relatively small but clear) body of evidence comparing traditional and standards-based curricula.

Overall, the evidence suggests the following. When you test for basic skills, there is likely to be little statistical difference in the performance of students from traditional or reform curricula � it�s mixed in the Senk & Thompson review volume � many of the reform curricula give lower skills scores, but not statistically lower. Overall, the best you can say is that it�s a wash.

However, when you test for conceptual understanding or problem solving performance, students from standards-based (reform) curricula are likely substantially to outperform students from traditional curricula.