There's a good deal of confusion about what it means to close the achievement gap in education. There's the question of what is being measured. Is it the difference in average standardized test scores? Is it grade-point averages? Is it dropout rates? Is it graduation rates? And there's the question of who is being measured. Is it students from wealthy families and those from low-income families? Is it black students and white students? Is it male students and female students? Different scholars use different definitions.