David is certainly effective; within just two sessions of tutoring I was scoring dozens of points higher on tests and quizzes, with one quiz even scoring 53 points more than the original! In addition to his effective teaching methods, having a relaxed, yet focused professional (as opposed to a hurried and intimidating teacher) made the idea of learning and understanding math much more approachable to me. Another fantastic quality of his tutoring services is that he doesn't stop helping when the tutoring session ends- he will continue to look over copies of your work, work further on problems gone unanswered in the sessions, and provide answers to the questions of students over e-mail and facebook. That in itself makes me more comfortable knowing that he is a dedicated professional. I am confident that I have a reliable source from which I can get super awesome math help. A+ tutor.