When it comes to the racial achievement gap, principals or teachers can have a bigger impact on achievement in one year than whether a child is poor or from a single-parent home, according to a Carnegie Mellon University professor.

At a Pittsburgh Public Schools education committee meeting last night, Robert Strauss, a professor in the Heinz School of Public Policy and Management at CMU, released a report on the racial achievement gap that he conducted with graduate students.

The study tried to identify the causes of the gap in which white students perform better than black students. Dr. Strauss noted the gap in grades 5, 8 and 11 ranged from 12 percent to 19 percent on the state tests given in the spring this year.

The study looked at 89 principals, 236 English teachers and 199 math teachers of students taking the Pennsylvania System of School Assessment tests in reading and math in March 2005.

He found that some principals and teachers didn't have a positive or negative impact on results. However, 62 principals had an effect on math results -- ranging from scores 17.5 percent higher to those 37.2 percent lower. And 33 principals had an effect on reading -- ranging from scores 15.66 percent higher to 35.65 percent lower.

Among teachers, 148 had a significant impact in math scores and 90 did so in reading, both also by a wide range, positive and negative.

Dr. Strauss said his study showed that those teachers and principals who made a positive difference helped both white and black students, not just students of one race or the other.

Dr. Strauss urged the district to find out what those who make significant differences are doing so other professionals can learn from them.

For various socioeconomic situations, the effect was typically in the single digits although the effects would be compounded for students who face multiple challenges over multiple years.

Linda Lane, deputy superintendent, also gave a presentation on the racial achievement gap, saying that race is a larger factor than poverty.

She said that black achievement levels vary widely across schools.

She noted specific efforts to improve achievement, including increasing "the work in ways which are specific to the needs of African-American students."