Curriculum guides what is taught while differentiation guides how it is taught. Differentiation can be used to teach the same standard to a range of learners by using diverse teaching and learning modes. Curriculum doesn't have to be narrow to increase chances of success on standardized tests. Rather, differentiation means that teachers can make math accessible, equitable, and exciting to all students by "providing materials and tasks on the standard at varied levels of difficulty, with varying degrees of scaffolding, through multiple instructional groups, and with time variations" (Tomlinson, 2000). Admittedly, standards-driven curriculum is far behind its goals for ensuring that "no child will be left behind."

But, while African-American and Hispanic students lag whites in achievement as measured by standardized tests, every racial/ethnic subgroup has made gains in achievement during the past few decades (it takes more than testing (closing the achievement gap, 2001). The gap has not narrowed since around 1988 because gains by black and Hispanic students did not exceed those made by other subgroups. Thus, as achievement went up across the board, blacks and Hispanic students would have had to improve at a faster rate to lower the gap. Still, the gap is worrisome and must be addressed. Some states are having success, not by taking measure to decrease accountability, but by forcing even greater degrees of accountability. For example, Texas requires its schools to show a minimum proficiency level in each student subgroup (Closing the achievement gap). Five years after implementation, the percentage of black students passing statewide exams increased by thirty-one percent and the percentage of Hispanic students passing the exam increased by twenty-nine percent. The percentage of white students passing the exam grew by eighteen percent during this same time. Thus, Texas closed its achievement gap...

Before its inception, our educational system was a mess. Now, progress is underway. However, there's more work to be done in helping teachers integrate differentiated instruction and standards-based curriculum and for implementing standards across a broader curriculum. and, there is a need for drilling down further on specific standards and measures such as in the Texas example.
Bibliography

Closing the achievement gap. http://www.subnet.nga.org/educlear/achievement/

English, F.W. (2000). Deciding what to teach and test: Developing, aligning and auditing the curriculum. Thousand Oaks, Calif: Corwin Press.

Fiske, E.B. (1998, February 9). Opponents want more freedom for schools to set own agendas: quest for standards splits U.S. educators. International Herald Tribune. http://www.iht.com/articles/1998/02/09/sover.t.php

Holladay, J. (2007, February). How stereotypes undermine test scores. http://www.tolerance.org/teach/activities/activity.jsp?cid=811

It takes more than testing closing the achievement gap (2001, Summer). http://www.masb.org/pdf/spreportsum.pdf

Lane, L. (2003, Spring) Standards deviation. A Child's Life. Vol. 25, No. 2. http://www.indiana.edu/~rcapub/v25n2/goodman.shtml

New York State learning standards. http://usny.nysed.gov/teachers/nyslearningstandards.html

Ravitch, D. (1995). National standards in American education: A citizen's guide. Washington, DC: Brookings Institution Press.

Tomlinson, C.A. (2000 September). How to differentiate instruction. Educational Leader. Vol 58, No. 1. http://www.ascd.org/ed_topics/el200009_tomlinson.html