A new survey suggests that President Obama’s victory last November had a positive effect not just on the academic expectations of black Americans; it might have raised parents’ interests in volunteerism as well, USA Today reports. The "Obama Effect," documented last winter, showed that Obama’s rise during the 2008 presidential election helped improve African Americans’ performance on skills tests, which helped narrow a black-white achievement gap. In the new findings, African-American parents of children in K-12 schools say they’re much more likely to volunteer in a classroom this fall, in effect narrowing a volunteering gap. The survey, being released Aug. 6 by GreatSchools, a San Francisco nonprofit that promotes parental involvement, finds a jump of 37 percentage points in the portion of African-American parents who say they’ll volunteer in their child’s school–now 60 percent, vs. 23 percent a year ago. GreatSchools CEO Bill Jackson notes that in several speeches, Obama has urged parents to turn off the TV, read to their children, and attend parent-teacher conferences. "That jump that we’re seeing … is clearly a response to that," he says…