Three years after a federal law required states to collect a host of education data, much of that information and more will now be available in one place--giving the public a newfound resource and giving educators headaches over how schools can be compared. On a free Web site to be launched on March 29, 2005, a public-private partnership will post test scores, school spending, student demographics, and other relevant data. The site will feature research tools that allow users to compare achievement across districts, track districts' and individual schools' progress in reaching student-achievement goals under the federal No Child Left Behind Act, and find schools and districts that may be outperforming others. The site--www.schoolmatters.com--also will give people ways to measure whether school spending translates into student learning, as well the chance to compare schools' effectiveness. Some educators have questioned whether the Web site provides a fair way to compare schools, especially in the section that calculates a school's "return on spending." State officials said that they would be watching how critics and supporters of public schools use the data to bolster arguments that specific schools should or should not get more money.