This chart, from a power point presentation by the Urban Institute, compares commonly accepted rates of graduation to recent studies conducted by diverse organizations like the Manhattan Institute, Urban Institute and the Education Testing Service. 

This is due in part because the U.S. Department of Education does not report an annual public school graduation rate for the nation and the most high-profile statistics are misleading.  

In addition, the emphasis on performance based accountability in No Child Left Behind sparked a plethora of state and national research.  It became apparent that there was no widely accepted or scientifically validated method for calculating graduation rates.  

Different calculation methods produce different results, however mounting evidence suggests that graduation rates are significantly lower then previously thought and there are large disparities between white students and students of color.