First, consider whether any outside issues, like anxiety, bullying at school, or even experimentation with alcohol or drugs might be contributing to your child’s performance, and address that through your pediatrician or a counselor. If it’s strictly an academic concern, put the grades into the context of the teachers’ grading expectations. Did your son just bomb one test that was heavily weighted? Or are two months of homework assignments gathered into balls of paper pulp in the bottom of his backpack? A little forensic work may offer the clues to what’s negatively affected his grade.