The Congress, among others, has been concerned about the academic achievement gap between economically disadvantaged students and their more advantaged peers. The disparity between poor students’ performance on standardized tests and the performance of their nonpoor peers is well documented, and there is broad consensus that poverty itself adversely affects academic achievement. For example, on the National Assessment of Educational Progress (NAEP) reading assessment, 14 percent of fourth grade students who qualified for the free and reduced lunch program (a measure of poverty) performed at or above the proficient level in comparison to 41 percent of those students who did not qualify for the program. Furthermore, research has indicated the importance of socioeconomic status as a predictor of student achievement. Research has shown that the achievement gap falls along urban and nonurban lines as well: students living in high-poverty, urban areas are even more likely than other poor students to fall below basic performance levels. In addition to the achievement gap between poor and nonpoor students, concerns exist that this gap may be related to differences between per- pupil spending among schools that serve poor and nonpoor communities. School district spending is generally related to wealth and tax levels, and differences in school district spending can have an impact on spending at the school level. Recently, efforts have been made to achieve greater spending equity. Using a variety of approaches, a number of states have targeted some additional funding to poor students to amend the unequal abilities of local districts to raise revenues for public schools. Comparing spending between schools in simple dollar terms provides one way to check for differences; however, this type of straightforward comparison may be insufficient to explain spending differences because it does not capture the higher cost of educating students with special needs. Schools with similar spending per pupil may actually be at a comparative disadvantage when adjustments are made to account for differing compositions of student needs. Though not definitive, some research shows that children with special needs—low-income students, students with disabilities, and students with limited English proficiency—may require additional educational resources to succeed at the level of their nondisadvantaged peers. Because these additional resources require higher spending, some researchers have adjusted per-pupil expenditures by “weighting” these students to account for the additional spending they may be required. Weighting counts each student with special needs as more than one student, so that the denominator in the expenditures to students ratio is increased, causing the weighted per-pupil expenditure figure to decrease accordingly. For example, a school with an enrollment of 100 students may have 20 low-income students, 20 students with disabilities, and 10 students with limited English proficiency. Weighting these three groups of special needs students twice as heavily as other students causes weighted enrollment to rise to 150 students. If spending per-pupil is $4,000 without weighting, it drops to $2,667 when weights are applied. The actual size of the weights assigned to low-income students, students with disabilities, and students with limited English proficiency is subject to debate and generally ranges between 1.2 and 2.0 for low-income students, between 1.9 and 2.3 for students with disabilities, and between 1.10 and 1.9 for students with limited English proficiency. The inner city schools selected for our study had high proportions of children in poverty in comparison to the selected suburban schools. The elected inner city schools also generally had more students with limited English proficiency than their suburban counterparts. However, the proportions of students with disabilities in our selected inner city and suburban schools differed within and among metropolitan areas. In Denver, the selected inner city schools consistently had a higher proportion of students with disabilities than the selected suburban schools while in Fort Worth, the suburban schools had a higher proportion of students with disabilities. (See table 1 for total enrollment and percentages of children in poverty, students with disabilities, and students with limited English proficiency for selected schools in the seven metropolitan areas reviewed in this study.) Differences in school spending can affect characteristics that may be related to student achievement. There is a large body of research on factors that may directly or indirectly contribute to student achievement. Spending has been the factor most studied for its effect on student achievement. Differences in student outcomes have also been related to factors such as teacher quality, class size, quality of educational materials, and parental involvement. Our study describes how some of these factors may differ across selected inner city and suburban schools. Differences in per-pupil spending between selected inner city and suburban schools varied by metropolitan areas in our study. Inner city schools in Boston, Chicago, and St. Louis generally spent more per pupil than neighboring suburban schools, whereas selected suburban schools in Fort Worth and New York almost always spent more per pupil than the inner city schools. In Denver and Oakland, no clear pattern of spending emerged. Three factors generally explained spending differences between inner city and suburban schools: (1) average teacher salaries; (2) student- teacher ratios; and (3) ratios of students to student support staff, such as guidance counselors, librarians, and nurses. When we adjusted per-pupil expenditures to account for the extra resources students facing poverty, disabilities, and limited English proficiency might need, inner city schools almost always spent less per pupil than suburban schools. To compensate for additional challenges faced by schools in these areas, federal education dollars are generally targeted to low-income areas. As a result, federal funds have played an important role in increasing funding to inner city schools. Differences between inner city and suburban school per-pupil spending were related to the particular metropolitan area studied and generally seemed to be most influenced by teacher salaries. The selected inner city schools tended to outspend the suburban schools in the Boston, Chicago, and St. Louis metropolitan areas. For example, in the Boston metropolitan area, the lowest spending inner city school spent more per pupil than the highest spending suburban school. (See fig. 1 for a comparison of per-pupil spending at selected inner city and suburban schools in these areas.) In contrast, in the Fort Worth and New York metropolitan areas, suburban schools generally outspent inner city schools. For example, among the selected schools in the Fort Worth metropolitan area, the lowest spending suburban school had per-pupil expenditures 21 percent higher than the highest spending inner city school. (See fig. 2 for a comparison of per- pupil spending at selected inner city and suburban schools in these areas.) In Denver and Oakland, an examination of spending differences among the selected suburban and inner city schools revealed mixed results. That is, analysis of spending differences showed no general pattern of spending that favored either inner city or suburban schools. (See fig. 3 for a comparison of per-pupil spending at selected inner city and suburban schools in the Denver and Oakland metropolitan areas.) Among the schools in our study, three factors influenced per-pupil spending: average teacher salaries, student-teacher ratios, and the ratio of students to student support staff. Average teacher salaries appeared to have the greatest impact on per-pupil spending, followed by lower student- teacher ratios and lower ratios of students to student support staff. Average teacher salaries influenced per-pupil spending in areas where inner city schools spent more per pupil (Boston and Chicago), where suburban schools spent more per pupil (New York), and where spending was mixed (Oakland). For example, in Chicago, where inner city schools generally outspent suburban schools, the median inner city school average teacher salary was $47,851, compared with $39,852 in the suburbs. In Oakland, where spending between suburban schools and inner city schools was mixed, the average teacher salary at the median spending school was $60,395 and per-pupil spending was $4,849, compared with $52,440 and $4,022 at the median spending inner city school. Student-teacher ratios and ratios of students to student support staff were factors that could offset the influence of teacher salaries in explaining per- pupil spending. For example, in Fort Worth, where the three suburban schools typically spent more per student than inner city schools, inner city teacher salaries were generally higher than suburban teacher salaries. However, ratios of students to both teachers and student support staff were lower in our selected suburban schools. For example, the median spending inner city school in Fort Worth had 21 students per teacher, compared with 17 students per teacher in the suburbs. Additionally, the median spending inner city school had 1 student support staff professional for every 162 students, whereas in the suburbs the ratio was 1 to 68. (Table 2 lists factors contributing to higher per-pupil spending—average teacher salaries, student-teacher ratios, and ratios of students to support staff—for the median spending school in each reviewed metropolitan area.) Despite higher per-pupil spending by about half of the inner city schools in our study, inner city schools generally spent less compared with neighboring suburban schools when spending was weighted to account for differing compositions of student needs. To account for the greater costs that may be associated with educating low-income students, students with disabilities, and students with limited English proficiency, some researchers have used formulas that weight these students more heavily than other students. In a similar fashion, we applied weights to our per- pupil expenditure data. The use of the lowest and medium weights had little impact on spending differences between inner city and suburban schools. Inner city schools in Boston, Chicago, and St. Louis continued to outspend neighboring suburban schools in most cases. For example, in Chicago, when students were weighted with the lowest weight, the median per-pupil spending for inner city school was $3,743 per pupil compared with $2,996 for the suburban school. Similarly, the use of medium weights generally did not result in higher per-pupil spending at suburban schools.