Less than one third of American eighth graders score in the two highest performance levels on the grade 8 mathematics test given by the National Assessment of Educational Progress. Only a little over one third of Massachusetts eighth graders score at the two highest performance levels on the state's own grade 8 mathematics test. In 2002, the Massachusetts Department of Education funded research to explore why there had been no significant growth in the percent of grade 8 students performing at the two highest levels on the state's grade 8 mathematics tests. An analysis of quantitative data obtained from administrators and teachers in a representative sample of 60 schools throughout the state in 2003 identified school-based factors that were significantly associated with the 20 of the 60 schools that both "increased above the state average increase" the percent of grade 8 students performing at the two highest performance levels on the state's grade 8 mathematics test and simultaneously "decreased above the state average decrease" the percent of grade 8 students performing at the lowest performance level. A significantly higher percent of teachers in these 20 schools reported spending a great deal of time reviewing and using test results, having a voice in the choice of their instructional materials, using accelerated and leveled algebra I classes to address the needs of above grade students, and less frequent use of calculators in non-algebra classes. At a time when teachers in all states are being held accountable for increasing the achievement of all their students, these findings warrant exploration on a nationwide scale. (Contains 17 tables and 11 footnotes.)