Several alternatives for teacher evaluation have been implemented:
Absolute standardized test scores: Teachers and schools are presumed to be effective if their students score well on standardized tests, and ineffective if they don't. In practical terms, this means that teachers of affluent, white, and Asian students are declared to be high-performing, and teachers of English language learners, poor, black, Latino, Native American students are declared to be low-performing.
Evaluation by school principals: The school principal makes a pre-announced visit to the classroom, to observe a specially prepared lesson. The observation usually lasts for less than one hour, and happens once or twice a year. Afterwards, the principal issues a written report, often containing a checklist and a narrative evaluation, that almost always declares the teacher's overall performance to be satisfactory. In some school districts, the evaluation may be performed by senior teacher rather than, or in addition to, the principal. Rarely, independent observers, typically managed by the district office rather than the individual school, conduct teacher evaluations. Principal-led evaluations are criticized for perceived favoritism and for sometimes giving passing scores to more than 99% of teachers in a district.
Evaluation by students: If asked validated questions, students as young as fourth graders can accurately identify effective teachers. Course evaluations are common in universities, but rarely count for more than a trivial fraction in a decision to retain or fire a teacher.
Activities outside the classroom: Part of a teacher's evaluation typically includes participation in staff training events. For example, a teacher who completes a master's degree is almost always paid more, even though holding a master's degree has no effect on student achievement.
Most experts recommend using multiple measures to evaluate teacher effectiveness.