I have criticized the various recent proposals floating around the country for new teacher appraisal systems on many grounds, including being instances of the fallacy of composition, which in this case means the notion that a complex activity like teaching, in its many different permutations in different subjects and grade levels, can be reduced to a single formula, to be applied uniformly across entire states. Reasonable friends might ask, "Okay, if you oppose these fomulas, what would you do? Surely you don't want to leave the status quo in place?"
Indeed I don't. What I propose is a single process oriented towards improvement for all teachers, rather than any single formula for judging their putative merit. Such a process would have all teachers meet with their immediate supervisors (ideally this would be a teaching inspector, but I'll save that idea for another post) near the start of the school year, say around October, to set targets related to aspects of their job description and to establish personalized professional development plans to help each teacher reach those individually chosen targets. A cycle of coaching sessions and follow-up meetings would continue during the year, with these oriented towards helping each teacher get better. Near the end of the year (somewhere between April and June), a summative appraisal meeting between the teacher, the immediate supervisor, and the administrator the next level up would write out the annual formal performance review, with the teacher's own written self-assessment discussed before management produces its formal appraisal, with its paragraphs detailing the supervisor's reasoning and with the teacher's performance crystallized in a number representing a holistic assessment of that performance while also utilizing the same scale that the school uses to assess its students and managers.