One of the most important factors in ensuring student success is quality instruction by teachers. However, quality instruction can be a difficult goal if teachers do not have the resources to improve their skills and if rising levels of teacher stress go unchecked. Now, researchers have found that high levels of job-related stress affect 93 percent of teachers, a greater percentage than previously thought. Classrooms with highly stressed teachers tend to have the poorest student outcomes, such as lower grades and frequent behavior problems.