Given the task definition and input, reply with output. This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: Public schools in Raleigh are operated by the Wake County Public School System. Observers have praised the Wake County Public School System for its innovative efforts to maintain a socially, economically and racial balanced system by using income as a prime factor in assigning students to schools. Raleigh is home to three magnet high schools and three high schools offering the International Baccalaureate program. There are four early college high schools in Raleigh. Raleigh also has two alternative high schools. Question: What is the school system praised for?
innovative efforts to maintain a socially, economically and racial balanced system