What factor is commonly assessed in determining teacher effectiveness?

Student performance on standardized tests is commonly assessed to determine teacher effectiveness because standardized tests provide quantifiable data that reflect student learning outcomes. These assessments are designed to measure educational achievement and the extent to which students have mastered the content that is being taught. The results can offer insights into how well a teacher is facilitating student understanding and engagement with the material.

Standardized test scores can be compared across different students, classes, and even schools, allowing for a clearer picture of educational impact. When used in conjunction with other measures, such as classroom observations and student feedback, standardized test results can contribute to a comprehensive evaluation of a teacher's effectiveness in promoting academic achievement.

While factors like longevity in teaching, participation in school activities, and availability for after-school tutoring are valuable, they do not directly measure the impact a teacher has on student learning in the same way that standardized test scores do. These other elements can influence a teacher's overall effectiveness, but they do not provide the same level of direct evidence of educational outcomes.