A new report says only about half of all students in the main school systems of America's largest cities finish high school. The report notes higher rates of graduation -- over 70% --in areas surrounding the cities. Researchers studied high school graduation rates from the 2003, 2004 school year. They also identified the nation's fifty largest cities. The largest, New York City, had a population of more than eight million. The smallest city was Wichita, Kansas. It had about three hundred and sixty thousand people. Researchers used a system of measurement called the cumulative promotion index to find graduation rates. School officials in many of the cities studied said the resulting numbers were too low. That is because different areas use different methods to find graduation rates. Critics say many methods do not give a true _ of the number of students who leave high school before finishing. Other studies have put the national graduation rate at about 70%. But experts agree that too many students are not completing high school. They estimate the number at more than one million each year. The report was prepared for America's Promise Alliance. The private group aims to help children receive services they need to succeed. General Colin Powell was chairman of America's Promise Alliance when it was formed in 1997. He attended the press conference Tuesday where the report was released. He said studies have shown that the US must do more to educate the leaders and work force of the future. Secretary of Education Margaret Spellings also spoke. She said the government will propose that states use the same methods when reporting graduation rates. Alliance officials also announced the start of a nationwide campaign to improve graduation rates. It is to include a series of meetings to be held in every state over the next two years. The meetings will bring together elected leaders, business owners, students, parents and education officials. They will develop plans to increase the number of Americans who finish high school. The author wants to tell us   _  .
too many Americans do not finish high school different methods to find graduation rates services American children need to receive the increase of the number of Americans who finish their high school