Professors from the University of Pittsburgh's Center on Race and Social Problems have done an analysis of "place-based college scholarships" including the Pittsburgh Promise. No link to the report has been located online, but here is an excerpt from the April 2011 paper, "PLACE-BASED COLLEGE SCHOLARSHIPS: AN ANALYSIS OF MERIT AID AND UNIVERSAL PROGRAMS":
"The Pittsburgh Promise and other merit aid programs primarily help students already planning to go to college to attend better quality colleges and reduce debt. These programs also produce a small increase in college enrollment, persistence, and completion rates, but they do not substantially improve K-12 student achievement, stop public school enrollment decline, or reduce poverty. Merit programs are also likely to substantially increase racial disparities in social and economic conditions since much higher percentages of white than black high school graduates receive the scholarship."
To improve K-12 achievement the report stated: "Most low-achieving students in center city school districts are minority and low-income. The best way to help these students is to provide comprehensive health, social, economic and educational services continuously from pre-birth through high school and additional assistance through college, as is done in the Harlem Children’s Zone."