The major purpose of the National Assessment of Educational Progress (NAEP) is to provide information useful for improving the quality of American elementary and secondary schools. NAEP has focused more on the measurement of academic achievement than on the need for information on learning contexts. Additional information is needed about why students perform as they do, and additional assessment of schools is desirable. NAEP has responded to its critics by treating and reporting all items separately and equally, countering the fear of creating a national curriculum. Recent efforts have strengthened test reliability and test validity, and earlier data has been reanalyzed to permit more reliable comparisons over time. NAEP data, although not as familiar as Scholastic Aptitude Test scores, have often been used to evaluate American education and achievement trends. However, more information is needed about learning contexts and school effectiveness: what works; causes of declines; and effects of peers, family, teachers, textbooks, curricula, finances, classroom organization, and special programs. Panel data comparing an individual's performance over the years while exploring contributing factors would be a costly but valuable data collection effort. NAEP might also be used to evaluate special education or compensatory programs, and national labor needs. (GDC)