Dressed in a gray suit, Doug Maclin stood behind a podium facing the panel of CPS board members, looking a bit uncomfortable. He was at the May meeting to brag about the changes he had accomplished during his short tenure as principal of Chicago Vocational Career Academy. Misconduct reports and suspensions were down. Attendance was up, to 80 percent from 68 percent. And though Maclin didn’t know it at the time, academics were on the upswing: The number of students who met or exceeded standards on the Prairie State Achievement Exam rose 2 percentage points last year, and the average ACT score increased by 0.4 points, a small but statistically significant improvement.